Flora Neotropica

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Dicranaceae: Campylopodioideae, Paraleucobryoideae Author(s): Jan-Peter Frahm Source: Flora Neotropica, Vol. 54, Dicranaceae: Campylopodioideae, Paraleucobryoideae (Feb. 21,

1991), pp. 1-237Published by: on behalf of New York Botanical Garden Press Organization for Flora NeotropicaStable URL: http://www.jstor.org/stable/4393822Accessed: 23-05-2015 15:49 UTC

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FLORA NEOTROPICA

MONOGRAPH 54

DICRANACEAE: CAMPYLOPODIOIDEAE, PARALEUCOBRYOIDEAE

by

Jan-Peter Frahm Department of Botany University of Duisburg

Germany

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\TYROPIOC

Of CANCER

FLORAO NEOTROPICA.

Published for

Organization for Flora Neotropica

by The New York Botanical Garden

New York

Issued 21 February 1991

^^ K^iN., *9


Copyright ? 1991

The New York Botanical Garden

Published by The New York Botanical Garden

Bronx, New York 10458

International Standard Serial Number 0071-5794

Library of Congress Cataloging in Publication Data Flora neotropica. - Monograph no. 1 - New York: Published

for Organization for Flora Neotropica by the New York Botanical Garden, 1968-

v.: ill.; 26 cm.

Irregular. Each issue has distinctive title. Separately cataloged and classified in LC before monograph no. 40. ISSN 0071-5794 = Flora neotropica.

1. Botany-Latin America-Classification-Collected works. 2. Botany- Tropics-Classification-Collected works. 3. Botany-Classification-Col- lected works. I. Organization for Flora Neotropica. II. New York Botanical Garden.

QK205.F58 581.98'012-dcl9 85-647083 AACR 2 MARC-S

Library of Congress [8508] ISBN 0-89327-363-5


DICRANACEAE: CAMPYLOPODIOIDEAE, PARALEUCOBRYOIDEAE

JAN-PETER FRAHM'

TABLE OF CONTENTS Introduction ................................................................................. 2 H istorical A ccount ............. ............................................................... 4 A natom y .... . . . . .................................................................... 5

G am eto phyte ............................................................................ 5 L eav es ..... ...................................................................... 5 C o sta . ..... .. ..... ... ...................... ................. ...... ................. . 6 R h izo id s ........................................................................... 9 Stem s .......................................................... .................. 10 Calyptrae ........................................................................... 10

Sporophyte ................................. ......................................... . 10 S etae .......... ....... ........ ................................. .. ....... ......... ... . 10 C apsules ............................................................................. 12 Stomata ........................................................................... 12 A nnulus ............................................................................. 12 Peristom e........................................................................... 12 Spores............................................................................... 14

C ytology ................................ .......................................... 14 C h em istry ................................................................................... 16 Geography .................................................... ........................ 17 O rigin and Evolution ......................................................................... 20 E co lo gy .. ................... ....... ................... ........................... 2 2

S u b strate ........................................ ..................................... 22 Structural Adaptations .......... .......................................................... 22

W ater Storage ........................................................................ 22 Resistance to W ater Loss .............................................................. 23

Uptake of W ater and Nutrients ................................................ ........... 23 Sexual R eproduction ...................................................................... 23 Vegetative Reproduction ................................................................. 24

System atic Treatm ent ......................................................................... 24 Cam pylopodioideae. ...................................................................... 24

1. A tractylocarpus .................................................................... 25 2. Bryohum bertia .................................................................... 31 3. Cam pylopodium ................................................................... 36 4. Campylopus ............................. ......................................... 37 5. D icranodontium ................................................................... 196 6. M icrocam pylopus .................................................................. 200 7. Pilopogon .........................................................................203 8. Sphaerothecium ................................................................... 216

Paraleucobryoideae ....................................................................... 217 1. C am pylopodiella ............. ................................................. 220 2. B rothera .......................................................................... 224 3. Paraleucobryum ................................................................... 225

A cknow ledgm ents ....................................... ................................... 229 Literature Cited .............................................................................. 229 Index to Scientific Names ............. ..................................... ............... 232

' Department of Botany, University of Duisburg, Fachbereich 6, Postfach 101629, 4100 Duisburg, Federal Republic of Germany.

1


~~~~~~~~~~~~2 ~~~Flora Neotropica

ABSTRACT

Frahm, J.-P. (Dept. of Botany, University of Duisburg, 4100 Duisburg, Federal Republic of Germany). Dicranaceae: Campylopodioideae, Paraleucobryoideae. Flora Neotropica 54: 1-238. 1991. The Campylopodioideae and Paraleucobryoideae are closely related subfamilies of the Dicranaceae (Musci). Within the Dicranaceae, both are characterized by a broad costa with a high variation in anatomical structures. The Campylopodioideae in the Neo- tropics consist of eight genera: Atractylocarpus Williams with three species, Bryohumbertia Portier de la Varde & Theriot with one, Campylopodium (C. Miiller) Bescherelle with one, Campylopus Bridel with 65, Dicranodontium Bruch, Schimper & Giimbel with four, Mi- crocampylopus (C. Miiller) Fleischer with one, Pilopogon Bridel with six, and Sphaerothecium with one species. The Paraleucobryoideae in the Neotropics consist of three genera: Brothera C. Miiller with one species, Campylopodiella Cardot with two, and Paraleucobryum (Lim- pricht) Loeske with two species. All 87 species, as well as infraspecific taxa are described and illustrated.

RESUMEN

Campylopodioideae y Paraleucobryoideae son subfamilias estrechamente afines a las Di- cranaceae (Musci). Dentro de las Dicranaceae ambas subfamilias se caracterizan por una costa ancha con una gran variaci6n de estructuras anat6micas. Las Campylopodioideae en los Neotr6picos consisten de 8 g6neros: Atractylocarpus Williams con 3 especies, Bryohum- bertia Portier de la Varde & Theriot con 1 especie, Campylopodium (C. Miiller) Bescherelle con 1 especie, Campylopus Bridel con 65 especies, Dicranodontium Bruch, Schimper & Giimbel con 4 especies, Microcampylopus (C. Miller) Fleischer con 1 especie, Pilopogon Bridel con 6 especies y Sphaerothecium con 1 especie. La Paraleucobryoideae en los Neo- tr6picos consiste de 3 g6neros: Brothera C. Miiller con I especie, Campylopodiella Cardot con 2 especies y Paraleucobryum (Limpricht) Loeske con 2 especies. Todas las 87 especies asi como los taxones infraespecificos estan descritos e ilustrados.

INTRODUCTION The Campylopodioideae and Paraleucobryoi-

deae are subfamilies of the Dicranaceae. This family of mosses is characterized by narrowly lanceolate leaves which are sometimes secund or falcate with (usually smooth) elongate to quadrate laminal cells which are often differentiated into basal and upper laminal cells, a single percurrent or excurrent costa, and the frequent occurrence of differentiated alar cells. The sporophytes are usually terminal with mostly cucullate calyptrae and cylindrical to ovoid, erect or curved capsules. The plants are erect and can be robust, forming dense mats, or minute. The Dicranaceae belong to an evolutionary line of the superorder Haplolepideae with a peristome consisting of 16 teeth. The peristome teeth of the Dicranaceae are entire or divided into 2 (rarely 3) prongs and usually are vertically striate on the outer surface,

an ornamentation which is frequently found in the Dicranales and therefore called the "dicranoid" type.

Unfortunately, there are transitions between the two subfamilies. Certain species of Campy- lopus cannot be distinguished vegetatively from species of Paraleucobryum, since they all have a "leucobryoid" structure of the leaves with ventral and dorsal rows of hyalocysts. Whether this is due to phylogenetic descent or the consequence of an independent evolution of this leaf anatomy is not known.

The Campylopodioideae were established by Brotherus (1924). Brotherus included 10 genera in this subfamily: Metzlerella, Microdus, Dicra- nella, Microcampylopus, Campylopodium, Campylopodiella, Pilopogon, Campylopus, Thysanomitrion and Dicranodontium. Of these genera, Thysanomitrion is now included in Cam- pylopus as a subgenus, Microdus and Dicranella


Introduction 3

are placed in a separate subfamily, Dicranel- loideae, and Campylopodiella is placed in the Paraleucobryoideae (Miiller & Frahm, 1987). In addition the genera Bryohumbertia and Sphaero- thecium are treated here (with species formerly included in Campylopus). The circumscription of the Campylopodioideae used here is similar to that of Walther (1983). Walther, however, seg- regated Campylopodium and Microcampylopus into different subfamilies (Dicranelloideae and Campylopodioideae), although both genera are very closely related and can be regarded as subgenera of one genus (Giese & Frahm, 1985a), and included Mitrobryum and Maireola in the Campylopodioideae. The placement of Mitro- bryum is not clear since this genus differs from all other Dicranaceae by its mitrate calyptrae. Maireola has been synonymized with Ditrichum (Frahm & Seppelt, 1987). The genus Bryotestua is not taken into account here because it is based on sterile plants. Another genus, Bartleya, has been placed into the synonymy ofDicranella cer- viculata (Crum & Anderson, 1981).

The systematics of the Campylopodioideae have been discussed by Frahm (1986) but there is still no satisfactory analysis of this subfamily. The circumscription given by Brotherus (1924) was ill-defined and based on five characters, three of which (dioicous sexuality, differentiated alar cells, and lack of stomata) were restricted by the word "mostly," a fourth character (differentiated perichaetial leaves) separated genera such as Di- cranella and Anisothecium into different subfamilies, genera which are today usually accepted as one genus. A fifth character (leaves gradually thinner towards the margins) is not applicable to most genera. This confusing assemblage of genera lacked revisions and monographs to provide the basic information for generic concepts. A conspicuous character met in most of these genera is the sinuose seta. Therefore it is commonly regarded as characteristic of the subfamily. Only Pilopogon and Atractylocarpus have straight setae, but these genera are virtually gametophyti- cally identical to Campylopus and Dicranodon- tium. Sinuose setae, however, also occur in Cynodontium (Dicranaceae), Grimmia (Grim- miaceae) and Campylostelium (Ptychomitri- aceae) and have apparently evolved indepen- dently several times. This may be the case for Campylopodium and Microcampylopus, which usually are placed in the Campylopodioideae be-

cause of their sinuose setae and thus their "cam- pylopodioid" appearance, but fit better in the Dicranelloideae in all other respects. Therefore, as treated here, the circumscription of the Cam- pylopodioideae is probably artificial.

Whereas most genera of Campylopodioideae comprise between 2 and 12 species worldwide, the genus Campylopus has about 180 species and is thus one of the largest genera of mosses.

With the exception of Campylopus and Di- cranodontium, all genera of Campylopodioideae have been revised: Campylopodium (Giese & Frahm, 1985a), Microcampylopus (Giese & Frahm, 1985b), Atractylocarpus (Padberg & Frahm, 1985), Pilopogon (Frahm, 1983a), Bryo- humbertia (Frahm, 1982a), and Sphaerothecium (Frahm, 1986b). Only two subgenera of Cam- pylopus have been treated worldwide (Thysano- mitrion, Frahm, 1984a, and Campylopidulum, Frahm, 1986c). For the rest of the genus only local treatments exist for South America (Frahm, 1975a, 1975b, 1977, 1978a, 1979a, 1979b, 1979c, 1980a, 1981a, 1981b, 1982c, 1984c, 1986d; Frahm & Hegewald, 1979; Frahm & Sipman, 1978), Africa (Frahm, 1985a), and Australasia (Bartlett & Frahm, 1983; Catcheside & Frahm, 1983; Frahm, 1984b, 1987a; Frahm & Mo- hamed, 1987; Frahm et al., 1985) as well as taxonomic treatments of single taxa (Frahm, 1974) mainly published in 14 continuations of the se- ries "Taxonomische Notizen zur Gattung Cam- pylopus" (Frahm, 1975c, 1976a, 1976b, 1976c, 1978b, 1978c, 1979d, 1980b, 1981c, 1981d, 1982d, 1985b, 1985c).

In these publications all character states needed for classification have been critically evalu- ated, the range of expression of these character states overviewed, the delimitation of genera defined and corrected, and many species placed into synonymy. Worldwide, the number of species in Campylopus has been reduced from about 720 to 180, in Microcampylopus from 12 to 2, in Pilopogon from 14 to 8.

The Paraleucobryoideae were also established by Brotherus (1924). Brotherus included the genera Paraleucobryum and Brothera and based the subfamily on the broad costa with a median row of chlorocysts, differentiated alar cells, a straight seta and symmetrical, smooth capsules. Recently Walther (1983) transferred Campylopodiella to this subfamily, based on the close relationship of this genus to Brothera. The entire subfamily


4 Flora Neotropica

has been monographed by Miller and Frahm (1987).

HISTORICAL ACCOUNT Campylopus was described by Bridel in 1819.

The name was chosen to characterize the curved setae (derived from Greek campylos = curved and pous = foot). Bridel included several species with curved setae in this genus which have noth- ing in common except this kind of seta, for example, species later placed in Grimmia or Ra- comitrium. Species placed presently in Campy- lopus were mostly described as species of Di- cranum, and many authors (e.g., Carl Miiller) continued to use the name Dicranum to describe hundreds of species applicable to Campylopus. The exploration of the tropics increased the number of species in this genus dramatically. The Index Muscorum (Wijk et al., 1959) lists more than 1000 species, about 720 of which were legitimate.

The high number of species described (e.g., 320 legitimate species cited in the Index Mus- corum for Latin America, and a total of 260 species described from Africa) prohibited an over- view of this genus. Different taxonomic concepts used in the last century led to the description of growth forms as separate species, and the lack of phytogeographic knowledge and pre-Darwinian theories on the origin of species resulted in the independent description of species from every country and island. The lack of knowledge of the variability of species and especially the use of variable character states, such as the transverse section of the costa, made this genus a difficult one. It enormously raised the number of species described; species which were neither illustrated nor sufficiently described.

During the last century many new genera were established or raised from subgeneric status.

Dicranodontium was introduced in 1847 for species formerly placed in Dicranum or Cam- pylopus.

Campylopodium, originally described as a section of Aongstroemia was raised to the rank of a genus in 1873 on the basis of its curved setae. At one time 27 different species were included; these have been reduced to two (Giese & Frahm, 1985a).

Microcampylopus was originally established as a subgenus of Campylopus in 1899. It was raised

to the rank of a genus in 1900, and again reduced to the rank of a subgenus in 1933. Of the 27 species included originally, three were retained by Giese and Frahm (1985b).

Pilopogon was introduced in 1826. In 1901 Brotherus placed all species of the genus Thysa- nomitrion in a subgenus of Pilopogon because of similarities of the peristome. This caused confusion, because Thysanomitrion was usually regarded as a subgenus of Campylopus. A monograph of the genus (Frahm 1983a) maintained eight species worldwide, seven of them neotropic.

The species of Bryohumbertia were originally included in Campylopus. The genus was based on an African species, described in 1939, which was regarded as more or less closely related or even synonymous with Campylopus. A re-eval- uation of its character states and additional ul- trastructural differences led to the establishment of this genus with three species, one each in the neotropics, tropical Africa and SE Asia (Frahm, 1982a).

Sphaerothecium was introduced in 1865 for a species from Colombia. In 1873 another species was added from Sri Lanka. For more than a hundred years these two species were the only representatives of this genus until a third species, from Africa and formerly a member of Cam- pylopus, proved to be a member of this genus (Frahm, 1986b).

Atractylocarpus was described by Mitten in 1869. Nineteen legitimate species were listed in the Index Muscorum. Of these nine were accepted in a recent revision of the genus (Padberg & Frahm, 1985).

The subfamily Paraleucobryoideae was defined by Brotherus (1924) to include the genera Paraleucobryum and Brothera. Walther (1983) added Campylopodiella, formerly included in the Campylopodioideae, because of its structural af- finities to Brothera.

Campylopodiella was described from Sikkim. Later an African and a Himalayan species were added. A revision showed the African species to be a species of Campylopus, the Himalayan species to be identical with the type species, and an andine species formerly regarded as Campylopus to be a member of Campylopodiella (Frahm, 1984c). In further studies (Miiller & Frahm, 1987) a third species, again from the Andes, was included in Campylopodiella. Recently a fourth


Anatomy 5

species was added from Papua New Guinea (Frahm et al., 1988).

Brothera was originally based on two nomina nuda from Asia. Brotherus (1901) reduced these names to synonyms of B. leana from North America, formerly included in Campylopus, and added a second species. This second species is a species of Campylopodiella (Frahm, 1984c), and so the genus is still monotypic.

Paraleucobryum was first introduced by Lind- berg (1886) as a subgenus of Dicranum. Loeske (1907) raised it to the rank of genus, and included three holarctic species. Subsequently other species were transferred to this genus from Dicra- num or described as new. All these new com- binations and new species have been reduced by Miiller and Frahm (1987).

ANATOMY GAMETOPHYTE

Most genera of Campylopodioideae and Para- leucobryoideae are dioicous. Only Atractylocar- pus is autoicous and Campylopodiella is paroi- cous. Conspicuously, these latter genera have species with small ranges. Dioicism is probably responsible for the broad morphological range of character states, especially in the genus Cam- pylopus, that are the results of numerous genetic variations resulting from out-breeding. Dioicy also has disadvantages, for example in long distance dispersal, when only one sex is present in one habitat and effective methods of vegetative propagation are required to fill the gap between heterosexual populations and to allow fertilization.

The sex of sterile plants cannot be determined. Fertile plants especially of the genera Campy- lopus and Pilopogon show, in part, a morphological differentiation due to heterodioicism. In C. fragilis dwarf males have been observed nest- ing in female tufts. Fertile plants of a number of species produce bud-like stem apices consisting of broader and blunter leaves. As in many other mosses this concerns mostly male plants, which produce flower-like gametangia that function for dispersal of the spermatozoids by a splash cup mechanism. More rarely, female plants also produce terminal buds which contain several perichaetia. There are also species that lack differentiation, or which display either hardly any or,

conversely, display extreme differentiation of gametangia. Conspicuously, the differentiation of bud-like perichaetia is confined to species with high fertility and it thus can be assumed that antherozoid dispersal is effective. Special differ- entiations are found in a group of species with piliferous leaves such as Campylopus introflexus, C. pilifer, C. julaceus and C. aemulans. Other species are mostly found fertile and thus give a comose appearance as in C. occultus, C. pauper or C. zygodonticarpus. The highest development of such perichaetia is found in Campylopus subg. Thysanomitrion. Here the perichaetia are developed on appressed foliate stalks, especially the species occurring in SE Asia. This character is not developed in the only subantarctic representative of this subgenus (C. clavatus) which is regarded as most primitive, and is hardly developed in the only neotropic representative (C. richardii).

Leaves

The leaves are lanceolate to narrowly lanceolate in shape, gradually narrowing to a subulate apex. The margins are usually entire or serrate or denticulate only in the apex. Due to the broad, often excurrent costa, the lamina is narrow and rarely reaches to the leaf tip, but often vanishes near midleaf. The lamina is always unistratose. Laminal cells can be differentiated into alar cells, basal and upper laminal cells. Alar cells may be differentiated or not. They are not developed in Microcampylopus and Campylopodium but differentiated in all other genera, either weakly or strongly. Although alar cells can be very conspicuous in some species and hardly developed in others, this is apparently not a specific character. In many species this character varies much, obviously controlled by the habitat. Alar cells function in water uptake from capillary water along the stem or the tomentum to the leaf. Therefore, alar cells are usually lacking in plants of wet habitats. In Campylopus pilifer specimens from rainforests show no alar cells since they receive atmospheric water taken up by the leaf surfaces. Specimens from dry habitats have differentiated alar cells. Alar cells are especially well differentiated in plants growing on wet rocks exposed to the sun, which have a high evaporation rate. In contrast to the older literature, which used this character for differentiation of species,


6 Flora Neotropica

the presence of alar cells is regarded today as controlled by modifications and thus usually ne- glected as a useful character for separation of species.

Basal laminal cells differ by their larger size and different shape from upper laminal cells. They can be either hyaline and thin walled or incrassate. Species with hyaline basal laminal cells usually show a distinct differentiation from the incrassate upper laminal cells. The basal cells extend higher up along the margins and are thus V-shaped in mass. Hyaline basal laminal cells sheathing the stem function for water uptake and are found especially in species of wet or mesic habitats. Incrassate laminal cells can be smooth or pitted. Basal laminal cells are differentiated into smaller outer and larger inner ones. The outer can be narrow and hyaline and forming a border 2-12 cells wide, or smaller and shorter. The upper laminal cells can be quadrate, oblique, oval or shortly rectangular. They are long-rectangular only in Dicranodontium.

Perichaetial leaves are widened at base and suddenly contracted to an elongate point. The broad sheathing base suggests a narrower costa, which is, however, not narrower but as broad as in normal leaves. The perichaetia themselves are surrounded by another type of broad involucral leaves which are blunt in male plants but show longly excurrent costas in female plants.

Special perichaetial leaves are found in Pilo- pogon, sheathing nearly the whole seta. This can be interpreted as another strategy to protect the young sporophyte. In genera of Campylopodioi- deae with sinuose setae the capsules develop protected between the comal leaves. This is not possible with straight setae but in this case the perichaetial leaves take over this function. This may also cause the longer shape of the capsules in genera with straight setae in contrast to the stout capsules of genera with sinuose capsules which stick between the perichaetial leaves.

Costa

The costa is percurrent or excurrent in all genera treated here. In Campylopus the excurrent costae may be concolorous or hyaline, forming whitish hairtips. These hairpoints can be erect (e.g., C. pilifer), reflexed (C. introflexus) or re- curved (C. griseus) and function in the reduction of evaporation. The length of the hairpoint is

determined by modification, since in all these species epilose plants can be found in shady habitats.

The costa is the most prominent character of both subfamilies. In contrast to most other mosses, the costa fills between 1/3 and % of the leaf width. In this way the usually unistratose lamina with a narrow costa of most mosses is replaced here, more or less totally, by a highly differentiated anatomical structure providing water storage, photosynthesis and mechanical protection against shrinking.

The costa is composed in most genera of Di- cranaceae, except numerous species of Campy- lopus and all species of Paraleucobryoideae, by a common dicranoid type. It consists of (Fig. 1):

1. A ventral chlorophyllose epidermis. 2. A multilayered band of long, narrow cells,

which are called stereids. Since they resemble similar cells in the central strand of the stem which function for water conduction, they are sometimes also called hydroids.

3. A median layer of enlarged cells, usually named deuters. The term deuter, of German origin, is merely descriptive and means pointer cell; it refers to conspicuously large cells in the median of a transverse section of a costa. This term has been used for a median band of enlarged cells in the Polytrichaceae. In that family these cells con- duct water, and therefore they are also called hydroids. In the Campylopodioideae, however, these cells are chlorophyllose ("chlorocysts") and are thus functionally different. Some authors re- place the term deuter by eurycysts (which means, however, the same and does not regard the function of these cells), others by "duces" (Latin for guide cells).

4. A dorsal band of stereids. 5. A dorsal epidermis. This structure primarily provides a firm struc-

ture and possible water supply by the two bands of stereids and assimilation by the ventral, median and dorsal cell layers.

In Campylopus an enormous variation of this type of costa is found, which is presumably the reason for the rich speciation in this genus. It allows the species to adapt to a broad spectrum of ecological niches (Frahm, 1987b). The variation (Fig. 2) concerns:

a. the change, by gradual enlargement from ventral stereids to substereids, small hyalocysts with firm walls and large hyalocysts with lax walls.


Anatomy 7

AigSfetea^ B^ssillSy t Al

if ,

FIG. 1. Transverse sections of leaves in different genera of Campylopodioideae and Paraleucobryoideae. A. Campylopodiella stenocarpa (Maslin s.n., NY). B. Paraleucobryum longifolium (Crum 1851, DUKE). C. Pilo- pogon macrocarpus (Allioni 8056, H-BR). D. Atractylocarpus longisetus (Pringle 10603, NY). E. Campylopodium medium (Steere 6831, MO). F. Microcampylopus curvisetus (Sartorius 60, BM).

b. the change from dorsal groups of stereids to substereids or single large cells. The stereids are sometimes named stenocysts, the large cells replacing a group of stereids, socii, comites, Be- gleiter or leptoids. These terms are taken from the structure of the costa in the Polytrichaceae in which these cells accompany the deuter cells

("socii, comites, Begleiter") and function for the transport of nutrients ("leptoids"), and form- together with the deuter cells-a primitive conduction tissue, with phloem (leptom) and xylem (hadrom) elements. This is, however, not the case in Dicranaceae and therefore an application of these terms should be avoided. All possible tran-


8 Flora Neotropica

A

B W

C O FIG. 2. Transverse sections of different types of costae in the genus Campylopus. A. Costa with large

ventral hyalocysts in Campylopus pittieri (Cleef 8806, U). B. Costa with ventral substereids in Campylopus surinamensis (Mohr 1868, NY). C. Costa with ventral stereids in Campylopus uleanus (Ule 148, H-BR).

sitions are possible from a group of stereids to a single larger cell by omission of one or more cell divisions (Frahm, 1982e).

c. the change from smooth dorsal leaves to ribbed or lamellose surfaces by division of the chlorophyllose dorsal epidermal cells.

As shown by the confusion of different terms used for the structure of the costa, there is no consistent usage. It is proposed to use the descriptive terms hyalocysts, eurycysts (for deuter cells), stenocysts and chlorocysts, although in the systematic part the term stenocysts is replaced by the more common and better understandable term stereids.

There is variation in the structure of the costa in one leaf and in plants of different habitats. The length of dorsal lamellae decreases to the leaf base and the width of ventral hyalocysts increas- es to the leaf base. Thus leaves may be lamellose

FIG. 3. Transverse section of the costa of Cam-

B 1!.

pylopus pilifer (Griffin et al. 92, FLAS). A. The upper third of the leaf. B. The lower third of the leaf.

in the upper part and ridged on the basal part (Fig. 3) or ridged in the upper part and smooth in the basal part. Ventral stereids in the upper part of the leaf can change to substereids in the basal part or substereids in the upper part can change to hyalocysts in the basal part. In humid habitats, dorsal stereids can get larger and change to substereids, and dorsal lamellae can get shorter.

In the Paraleucobryoideae the costa consists of a median band of chlorocysts (perhaps comparable to the deuter cells of the Campylopo- dioideae) and ventral and dorsal hyalocysts. The median chlorocysts are single in Paraleucobryum and Brothera but divided into 2 to 4 in Cam- pylopodiella. In Paraleucobryum a dorsal band of chlorocysts can be present. This situation links Paraleucobryum with certain species of Cam- pylopus (Frahm, 1982b). Considering the basic sporophytic differences between both genera this can be interpreted rather as independent development than as phylogenetic linkage. On the other hand, Ligrone (1985) has derived the structure of the leucobryaceous leaf from a dicranoid ancestor, which is also hypothetically possible and


Anatomy 9

phylogenetically even more likely, since Leuco- bryum has the same sporophyte as species of Dicranum.

The presence of dorsal and ventral bands of stereids in most other Dicranaceae can be regarded as the basic structure from which the ten- dency to develop hyalocysts seems to be derived. The presence of ventral and dorsal bands of stereids in the highly advanced subgenus Thysa- nomitrion need not be a contradiction. These species, all except for one, occur in the tropics, where the conservative structure of the costa with stereid bands has advantages as protection against shrinking and for water support.

The ecological significance of the costa of Campylopus has been discussed by comparisons of species pairs differing only in a single character in the costal anatomy and a different habitat (Frahm, 1987b). The differentiation of the costa concerns several characters.

1. Lamellose and non-lamellose costae. There are all possible transitions between costae with smooth dorsal sides and dorsal sides with lamellae up to six cells high in different species of this genus. Generally, species with high lamellae occur in habitats which can easily dry up. Species with long lamellae can store water and thus extend the photosynthetically active period in dry habitats. Examples for this adaptation are C. trachyblepharon (on dry sand in coastal areas of SE Brazil), C. pilifer on exposed rocks, and C. lamellinervis in dry caatinga forests. Conspicu- ously, C. pilifer var. lamellatus has lamellae six cells high, but it occurs not in drier habitats but in rainforests. It can be assumed that the lamellae also allow a better gas exchange in rain forest habitats with higher humidity and higher temperatures.

2. Ventral hyalocysts and ventral stereids. In more than half of the species of Campylopus the ventral stereids in the transverse section of the costa of most Dicranaceae are replaced by ventral hyalocysts. As shown by often narrower adaxial cell walls, these hyalocysts function for water storage. The size of the hyalocysts varies between 14 and % of the leaf width. Species with lax hyalocysts occur in wet habitats (as in many paramo species, e.g., C. jamesonii, C. cavifolius, and C. nivalis). Species of mesic habitats have smaller hyalocysts with firm cell walls. In dry habitats species show ventral stereids as protection against shrinking. This is best demonstrated

by the ventral stereids of C. pilifer ssp. galapa- gensis, which occurs on dry lava flows, and C. pilifer ssp. pilifer which, with ventral hyalocysts, occurs in less exposed habitats (Frahm, 1987b).

3. Dorsal stereids and dorsal substereids. Dorsal stereids occur in bundles of 2-4 cells and function presumably for mechanical fixation and perhaps also water transport. In some species these stereids are replaced by one nonstereidal cell (which has a small lumen and therefore is usually called substereidal). As in species with large ventral hyalocysts instead of ventral stereids, these species without dorsal stereids are also characteristic of wet habitats, such as dripping cliffs or swamps.

Hyalocysts have usually been interpreted as water storage cells. This is somewhat in contradiction of the fact that species with hyalocysts often occur in hygric habitats, where this function is not needed. Another possibility (in anal- ogy to Sphagnum) is that they function in the uptake of nutrients in swampy habitats. Recently Robinson (1985) added another theory. Robin- son observed air bubbles in the hyalocysts of Leucobryaceae and Calymperaceae from tropical lowland forests and supposed that these air bubbles can also function to allow a better gas exchange for the chlorocysts situated in the median of the costa, for chlorocysts surrounded by cells filled with water would have a restricted gas exchange. The same may be the case for species of Paraleucobryoideae with ventral and dorsal bands of hyalocysts and also for some species of Cam- pylopus. However, in the Paraleucobryoideae as well as in Campylopus, pores in the surface of the leaves have not yet been observed as in Leu- cobryaceae and Calymperaceae, indicating not only a structural but also a functional difference.

Rhizoids

Rhizoids can originate from the basal parts of the stems and the lower dorsal part of the costa. Only in Dicranodontium and Atractylocarpus are rhizoids also borne on the ventral part of the costa (Crundwell, 1979), showing the close relationship between the two genera. Only stem- borne rhizoids are found in Campylopodium (Crundwell, 1979) and Microcampylopus (as in Dicranella and Microdus) showing in this (and other respects) connection of these genera to the Dicranelloideae rather than to the Campylopo-


10 Flora Neotropica

dioideae. Thus leaf-borne rhizoids may be a good character of the Campylopodioideae in a revised sense. They can be lacking, scattered or form a dense tomentum. Since rhizoids function for an external transport of water, low species (such as species of Sphaerothecium, Campylopodium, Microcampylopus or Brothera) have usually few or no rhizoids. Even in larger species this character seems to be controlled by the environment. It seems therefore to be as unstable as the presence of alar cells, which cooperate with the rhizoids in the transport and uptake of water. A tomentum is found especially in those species forming dense cushions such as many paramo species. Sometimes the color of the tomentum has been used for identification. However, rhizoids are generally reddish in normal light and orange brown in transmitted light in older parts by incorporation of phenolic compounds in the cell walls and whitish in normal light or hyaline in transmitted light in younger, outer parts. Thus a dense tomentum may look whitish as seen from the outside but is reddish inside. Only the hyaline tips of the rhizoids seem to resorb water.

The structure of the surface of rhizoids has been successfully used for differentiation of species in some mosses but has been studied only in detail for Campylopus (Frahm, 1983b). Rhi- zoids are usually smooth but a few species with papillose rhizoid surfaces have been found.

Recently rhizoid gemmae have been found in a species of Campylopus from Europe (Arts, 1987) and in one species from the neotropics. They may, however, have been overlooked, since such gemmae were not expected in this genus.

Stems

The stems show an internal differentiation into an outer cortical layer with firm, thickened cell walls, a median parenchymatic tissue and a central stand of small, narrow, elongate cells (Fig. 4).

Calyptrae The calyptrae are cucullate in all genera. This

concerns more or less ripe capsules. In young sporophytes the capsule is fully covered by the calyptra which is symmetric at this stage and not split. Indications of mitrate calyptrae for genera such as Brothera in the literature probably de-

pend on such early stages of development. The calyptrae may be ciliate or entire at base. This character seems to be fixed genetically and has been used for differentiation of species in Cam- pylopus but must be used with some caution, since in Campylopus ciliate and non ciliate ca- lyptras have been found in the same species. It can be supposed that in humid habitats the tissue of the calyptra may grow on after separation from the vaginula and thus form cilia. In dry habitats the calyptra may not develop cilia or the cilia are broken off. Cilia are especially long and conspicuous in Campylopus subg. Thyanomitrion and subg. Campylopidulum.

SPOROPHYTE

Sporophytes usually arise terminally from the gametophyte. Pseudolateral insertion has been found only in a few species of Campylopus, such as C. shawii and C. controversus.

Setae

The setae are comparable short. In Sphaero- thecium they are only 3-4 mm long and immersed in the perichaetial leaves. Notably, all three species of Sphaerothecium, found in Co- lombia, South Africa and Sri Lanka, are known only from small ranges covering a few square kilometers. In Microcampylopus the setae are also only 2-6 mm long but not immersed in the leaves. In Campylopus the setae are usually 8, rarely 12 mm long and in Bryohumbertia and Atractylo- carpus the setae reach a maximum length of 15 mm. The short length of the setae indicates an origin of the genera in open habitats, where the capsules are exposed to the wind, and not in forests or similar habitats, where a short seta would be a disadvantage.

The setae show an interesting twist mechanism. They are twisted in the dry state and uncoil when they are wetted even by water vapor. Al- though this effect has been known for more than a hundred years, the mechanism for this torsion was not known until recently. Noticeable in all species with coiling setae, the outer cortex of the setae has strong asymmetric thickenings. Recent SEM and TEM studies (Frey & Frahm, 1987) have revealed that there are groups of small pores 80 A in diameter in the primary and secondary cell walls of the epidermis layer. Water or water


Anatomy 11

^

''

-. ? : ' . '.

FIG. 4. Transverse sections of stems in different genera of Campylopodioideae and Paraleucobryoideae. A. Pilopogon macrocarpus (Allioni 8056, H-BR). B. Atractylocarpus longisetus (Pringle 10603, NY). C. Microcam- pylopus curvisetus (Sartorius 60, BM). D. Campylopus richardii (Griffin et al. 1035, FLAS). E. Campylopodiella stenocarpa (Maslin s.n., NY). F. Campylopodium medium (Steere 6831, MO).

vapor can pass through them and be absorbed by pectine in the microfibrils of the incrassate tertiary cell walls. These microfibrils, coiled in the dry state, enlarge, causing an uncoiling move- ment of the setae. The setae are straight in some genera (Atractylocarpus, Pilopogon, Paraleuco- bryum) but sinuose in all other genera. This shape originates when the seta first grows upwards and

then curves downwards. In this manner the young sporophyte becomes situated between the perichaetial leaves, where the capsule develops protected against desiccation. When the capsule is ripe the seta grows upward again, producing a second curve and thus a sigmoid shape to the seta. In this way the calyptra is frequently left between the perichaetial leaves. The sigmoid


12 Flora Neotropica

shape of the seta causes wide movements of the capsule when the seta is uncoiling. In these genera the setae are twisted dextrorsely in the upper part but sinistrorsely in the lower part which prevents the setae from being torn off by the uncoiling movements.

Capsules The capsules are 1.5-2 mm long in the Cam-

pylopodioideae. They are globose (Sphaerothe- cium, Campylopus subg. Campylopidulum), long cylindrical (Pilopogon, Atractylocarpus), or ovoid to short-cylindrical, especially when empty. They can be straight and symmetric or curved and asymmetric, the latter often being strumose (Fig. 5). The color varies between yellowish in young capsules to dark brown on old capsules. When emptied, the capsules are furrowed and contracted below the mouth. In the Paraleucobryoideae capsules are cylindrical. Seta length and capsule orientation are important for spore dispersal. Conspicuously cylindric capsules are correlated with long, erect, nonsinuose setae, as in Atrac- tylocarpus and Pilopogon. Here the spores are released by vibrations of the setae by wind. In genera which have the sophisticated twist mechanism combined with sinuose setae, the spores are shed by spiral movements of the setae. In Campylopus both symmetric, upright and asymmetric, curved capsules are found. Species with conspicuously upright capsules usually occur in open habitats, whereas those with curved capsules grow in forests.

In the Paraleucobryoideae the capsules are always erect, shortly to longly cylindric, and 1.5 mm to 2.5 mm long.

The operculum is about half as long as the urn and obliquely rostrate in most genera and longer in Bryohumbertia. It is usually darker colored than the urn.

Stomata

Stomata at the base of the capsules are found in Campylopodium (Campylopodioideae) and Paraleucobryum (Paraleucobryoideae, although there are no stomata indicated in the literature), conspicuously only in these representatives of different subgenera, but not in closely related genera. They are cryptoporous in Campylopo- dium but phaneroporous in Paraleucobryum.

Annulus

An annulus is present in the Paraleucobryoi- deae in Brothera and in Campylopodiella stenocarpa. It is apparently lacking in the Campylo- podioideae, although in Campylopus there are sometimes indications of an annulus found in the literature.This seems, however, to refer to an annulus which is visible microscopically as differentiated cells but not dehiscent.

Peristome

The peristome consists of 16 teeth which are usually split to half (or more) their length. Only in the two species ofPilopogon subg. Thysanomi- triopsis and in the monotypic genus Brothera are the peristome teeth not divided. There are two types of peristome teeth: the so called dicranoid type consisting of elongate triangular teeth, which is common in most genera, and another type consisting of narrow, filiform teeth (Fig. 6). The abaxial surface of the dicranoid peristome shows longitudinal striae, the adaxial surface has transverse ribs, usually densely covered by papillae (Fig. 7, except for Bryohumbertia). In the dry state the peristome is closed because the inner transverse ribs, forming U-shaped structures, are dried up and bent inwards. When moistened (fa- cilitated by the papillae) the tension between these ribs is lowered, the distances between these ribs are enlarged by absorption of water vapor and the peristome teeth move outwards. By this mechanism spore dispersal is possible in moist conditions. At the same time the setae uncoil, resulting in despiralizing movements or, in genera with sinuose setae, resulting in wide circular movements. Due to the moist condition when the spores are released they are probably not dis- persed far. This has some importance for these genera that are dioicous because female and male spores must fall nearby to allow fertilization in the mature plants. Filiform peristome teeth occur in Campylopus subg. Thysanomitrion and in Pilopogon. Both genera show strong resemblance also in gametophytic characters, but are distinguished by sinuose setae in Thysanomitrion but straight setae in Pilopogon (which shows that this character is perhaps overvalued). Here the peristome teeth are longer, ending in slender, round apices which are papillose. The broader basal part of the teeth (lower 1/4) has the same structure


Anatomy 13

< / / ft fI"/

A / I I B

B(B

A ; " i W V i U

fl

K

if- H

FIG. 5. Shape of capsules in different stages of development in the genus Campylopus sect. Homalocarpus (A-D) and sect. Campylopus (E-H). A. C. nivalis (Sharp 3043, TENN). B. C. areodictyon (Griffin 356, FLAS). C. C. argyrocaulon (Hegewald 9171, hb. Frahm). D. C. occultus (Puiggari 331, H-BR). E. C. arctocarpus (Vital 4264, SP). F. C. pauper (Lindig s.n., H-BR). G. C. chrysodictyon (=pauper) (Lindig s.n., NY). H. C. concolor (Lindig s.n., NY).

as in the common dicranoid type. In addition to the opening mechanism described above, the long apices of the peristome teeth are twisted when in the dry state but uncoil when moistened (as

in the pottiaceous type of peristome). In both groups only the one representative of Pilopogon in Africa and the only representative of Thysano- mitrion in the subantarctic (which are regarded


14 Flora Neotropica

VAaz~~~~~~~~~~isi

11' O

or , o? "

'It,

n.y

FIG. 6. Types of peristomes in Campylopodioideae. A. Entire peristome teeth in Pilopogon laevis (Lindig s.n., H-BR). B. Bifid peristome teeth in Microcampylopus curvisetus (Sartorius 60, BM).

as the most primitive species) have the normal dicranoid type of peristome. It can thus be assumed that the species of Pilopogon in South America developed after separation of the Gond- wana continent, caused by changing ecological conditions stemming from the uplift of the An- des, while Pilopogon africanus remained un- changed in Africa. In this regard the neotropic type of peristome would be the most advanced. The same can be assumed for Thysanomitrion, in which species evolved from the present subantarctic ancestor and extended to the tropics with a special speciation in SE Asia.

Spores The spores are ca. 10-19 um in diameter in

most genera and are therefore best adapted for long distance dispersal. Only in Campylopodium and Microcampylopus are they 18-24 Atm, ca. 21 Lm in Sphaerothecium and 19-34 um in Paraleu- cobryum. In the numerous species of Campylo- pus and species of Bryohumbertia and Pilopogon spore size is remarkably uniform at ca. 13 Am.

The spore ornamentation is not yet known by SEM studies for all genera. To the extent that the genera have been studied, it varies between nearly smooth to finely or coarsely papillose in Cam- pylopus to warty in Microcampylopus and Cam- pylopodium (Figs. 8, 9). This does permit separation of subgenera and sections in Cam- pylopus (insofar as this can be generalized from the comparatively few species which have been studied) and even species in Microcampylopus and Campylopodium.

CYTOLOGY Chromosome numbers are known for only 18%

of the mosses, mainly for species of Japan, Eu- rope, North America, India, Australia or Ant- arctica. Very little is known about tropical mosses. According to Fritsch (1982) there are no counts for Atractylocarpus, Pilopogon, Sphaerothecium or Bryohumbertia. For Campylopodium n = 13 + m and 35 + 1 are given, but the count of the first species belongs to Microcampylopus after a


Cytology 15

. E . > ,~~~~~ / / '. ? ._, /.

. . / ,:.. '~./,~...

.% /,

t z,,~7

!? i> @

"' ~ ; c ,;t ;~, r fii

A- III' ' a , A /' , !

I~ ~ % i _ _? , 'i~J ' 'tf.'/X

, ~;r?

-[~~~~~~ . : 2 ' , / f' ~ a~IB / ,

?I , i". ~ , ~.

? ~ . z~ '~ z

_ \ - N ' ' .

FIG. 7. SEM pictures oflpenstomes. A, B. Bryvohumbertiafilifolia (Frahm 1555, hb. Fralm). C. Campylopus

occultus (Ge 2, JE). D. Atractylocarpus longisetus (Pringle 10603, NY).'

__Xs~~ ?-?/ ;r hs w# S{ }

__ (?. ?r ' t ; i

S_;;li'g, ' tL'^'.

l~~~nii, _I?s _

~~~~~~~~~Ir j ! t r 'if: _=~~

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?f

1 *e l - T

_;*,~~j~ t, jt. ?D -- ' _,,_.st1 i ' Si i'X

;~~~ -1 : , ^~~~~~~~~~~~~~~~~~~~~~~~- 1. A. _ hy+"~~. t 1F

_ : t~~~~ ~ ~ ~ ~ ~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ tt - < - il < _ l~~"? ;0?

tM ~ ~ r Bb'je _ Ba n, L ocutu Ghr 5, J)D.Arcyoaps logseu (Pinl 1063 Y)

revision of the genera (Giese & Frahm, 1985a, 1985b) and the second count concerns a species of Dicranella. This shows that chromosome counts are highly dubious for genera which have not been revised or are from species which have been erroneously identified, which again concerns mostly tropical species. In the one species of Dicranodontium studied cytologically, n = 11-

12 are found in different parts of the range. Chro- mosome numbers in Campylopus are known from 14 species (=approx. 7% of the actual number of species, Frahm, 1983b), and one of them is now transferred to Bryohumbertia. None of these counts is from neotropical material. This is partly due to methodological difficulties. Only two of these counts were taken from mitosis, all oth-


16 Flora Neotropica

'. .

FIGs l s ( l 1 , N . B. FIG. 8. Spores ofCampylopodioideae. A Atractylocarpusl 1ongisetus(Pringel 10603, NY). B. Campylopodium

medium (Steere 6831, MO). C. Campylopus caroinae(Yital 1714, SP). D. Microcampylopus curvisetus (Sartorius 60, BM).

ers from meiosis, which are more easily obtain- able. However, only a few of the species of Cam- pylopus produce sporophytes consistently and the sporophytes of numerous species are not even known. The basic numbers are 10, 11, 12, 13 and 18. Chromosome numbers of 10-14 are commonly regarded as basically diploid (New- ton, 1984) and thus all species of Campylopus can be regarded as diploid, two of them with n = 18 also triploid. Although most counts are taken from one population only and not from different populations, especially in species with transcontinental ranges, the results presented are too similar to expect surprises in additional results. This is not different from most Dicranales in which n = 13, 14 are found, probably poly- ploids of n = 7. In the Paraleucobryoideae n = 12 is given for Brothera leana. For the genus Campylopodiella n = 14 + m is reported based on one count in one species and n = 12 or 14 for Paraleucobryum longifolium. As in the Cam- pylopodioideae all counts fall into the same range of the Dicranales.

CHEMISTRY Flavonoid patterns of several species of Cam-

pylopus (Frahm, 1983b), Pilopogon, Campylo- podium and Microcampylopus (Frahm, unpubl.) have been studied. In Campylopus different flavonoid patterns allow separation of subgenera and sections. Surprisingly, in two species of Campylopus (C. albidovirens, C. pittieri from the neotropics) no flavonoids have been found. Both species vegetatively much resemble the genus Paraleucobryum, which also has no flavonoids (Muller & Frahm, 1987) and seems to indicate a phylogenetic connection between these two genera of different subfamilies. However, Leu- cobryum, a genus with a similar anatomical structure of the costa, also has no flavonoids (Hu- neck, 1983), although the genera may not be closely related (Loeske, 1907). Other chemical constituents of the Campylopodioideae and Par- aleucobryoideae have not been studied very much. In Campylopus introflexus steroids such as campesterol have been found as well as the


Geography 17

_(* W** .fiC. i~Ia

I, 4L

FIG. 9. SEM photographs of spores of Campylopodioideae. A. Campylopus flexuosus (Hakelier s. n., hb. Frahm). B. Campylopus occultus (Gehrt 352, JE). C. Bryohumbertia filifnolia (Frahm 1555, hb. Frahm). D. Atractylocarpus longnisetus (Pringle 10603, NY).

'

'~ ~ ~ ~~~P "'a .... '~~~~~~~~~~LI I? r --3C_L~~~~~~~~~~~~~~~~~~~ "~~~~~~4~~~~,"~~ '74 ~ ~~f $;

L ~'l,. FI. 9 E ho orpsopoefCmylpdoda.A.Cmyou iexou (H k eir s.n. hb. Fram) B Crnylpu cutu (Ght32 E.C rohmetaflfla(rhr 55 a.Fam.D

Atatyoaru lni s ts(ri n 100,N)

triterpenoid hop-22(29)-ene (Huneck, 1983), but these few results have no systematic significance. In many species of Campylopus, Dicranodon- tium, Bryohumbertia and Pilopogon, lipids can be observed in the cells of the lamina and costa. This effect is visible only in species with firm basal laminal cell walls and not in those with hyaline, thin cell walls (and thus not in species of Paraleucobryoideae). Tropical species have firm cell walls in the lower part of the leaf, whereas subantarctic and andine species have hyaline basal laminal cells. Since lipids function as re- serve substances it may be supposed that these lipids function for balancing the energy loss by

respiration which is especially critical for ecological conditions of the tropics.

GEOGRAPHY

Range extent differs considerably in the genera of the Campylopodioideae and Paraleucobryoi- deae. It is smallest in the genus Sphaerothecium, in which all three species are known only from a few records within a few square kilometers. In contrast, the range of the genus Campylopus comprises nearly the whole world between 65?S and 70?N latitude and an altitudinal range between sea level and 4800 m. This extreme dif-


18 Flora Neotropica

ference is mainly due to different structural and ecological adaptations, which are treated in detail in the chapters on anatomy and ecology.

Pilopogon is represented in tropical Africa with one species, in Central and South America with seven. Only one of these species ranges widely through Central America, the Caribbean and to Brazil; all other species are confined to larger or smaller parts of the Andes (which can therefore be regarded as a centre of radiation of this genus), either by geographical isolation (as in P. schilleri from Chile) or habitat diversity (as in P. tiquipayae or P. macrocarpus).

Dicranodontium is a mainly holarctic genus. Only a few species are found in the tropical mountains of South America, Africa and SE Asia, probably derived from holarctic ancestors, since these species are mostly confined to the northern parts of the tropics and rarely cross the Equator.

Bryohumbertia is represented with one species each in the neotropics, tropical Africa and SE Asia. All three species are apparently very closely related, the taxa in Africa and SE Asia being more closely related than either of these is with the neotropic species.

Microcampylopus is also represented in the tropics with one species each in the neotropics, Africa and SE Asia. The African species occurs also in SE Asia.

Campylopodium comprises two species, one with a wide circumpacific distribution from Ja- pan to New Zealand and Chile, the other endemic to New Zealand and Tasmania.

Atractylocarpus comprises nine closely related species worldwide. All species are confined to alpine habitats. There is one species each in all mountain massifs of the world and thus no over- lapping ranges. The ranges vary much in size, between Eurasian in A. alpinus and endemic species, like A. madagascariensis.

Paraleucobryum is again a holarctic genus comprising three species of which one (P. enerve) goes down to Central America. Only one taxon (P. longifolium ssp. brasiliense) occurs in the tropics and is endemic to SE Brazil.

Brothera is monotypic and has a disjunct range between East Asia and SE of North America and Mexico, probably as a relict of a former amphi- oceanic range in the Tertiary.

Campylopodiella shows a similar disjunction, but at the generic level, with one species in the Himalayas and two in Central and northern South

America. The neotropical species are separated by a different altitudinal range and have probably evolved from the same ancestor in the course of the Andean folding.

Most species are found in subtropical, tropical montane or tropical alpine regions and do not occur in the lowlands of equatorial latitudes. Only a few species of the better adapted and (according to the number of species) most successful genus, Campylopus, can survive here. These species (C. surinamensis, C. savannarum) are confined to open, light habitats such as sandy shores of rivers or sandy soil in heath forests. This effect is probably caused by physiological problems. In ex- periments, tropical montane species did not reach a sufficient net photosynthesis under lowland conditions with high temperatures and low light intensity (Frahm, 1987c, 1987d). Only taxa that are physiologically specially adapted seem able to grow in the understory of the equatorial rainforest. A higher light intensity in open habitats allows the species mentioned above to compen- sate for the high rates of respiration in part. It remains an open question why those species of Campylopus found in the Amazon lowland occur only on sandy and not on lateritic soil.

In Campylopus all types of distribution, from tropical disjunct species to endemic taxa, are found. There are only a few species occurring throughout the tropics. If ranges cover South America, Africa and Asia (as in C. pilifer or C. savannarum), the distribution in Asia is confined to India and Sri Lanka. Such species are replaced in SE Asia by vicariant species, which demon- strates that isolation of SE Asia by continental drift happened earlier than the isolation of India from Africa or Africa and South America.

There are several phytogeographical relations to Africa. Several species are disjunct between Africa and South America. Inasmuch as they are either lowland species (Campylopus savannarum), montane (C. flexuosus, C. fragilis), or alpine species (C. nivalis, C. incacorralis, Frahm, 1982b) and also species which produce spores either frequently or extremely rarely, seems to indicate that both long distance dispersal (especially of fertile alpine species) as well as separation of populations by continental drift (of sterile lowland species) can be considered as rea- sons for these disjunctions. It highlights the fact that at least the lowland species may be older than the separation of South America and Africa


Geography 19

at the end of the Mesozoic. Comparing the number of species in both continents, Africa has, with 50 species of Campylopus, fewer species than South America, with 65 species. This is partly due to a richer speciation of this genus in the Andes. Although the isolated mountain massifs in Africa seem to support endemism by isolation, this is not the case in Campylopus. In contrast, this situation in Africa seemed to interrupt possible migration routes and caused small ranges of species. Air currents in the tropics generally go from east to west (van Zanten 1983) and therefore the origin of the alpine species occurring in Africa and South America should be African. This is difficult to imagine, since these alpine species have apparently evolved from subantarctic ancestors and had a better pathway to the tropical mountains in South America through the continuous Andes rather than, as in Africa, by hopping from one mountain to the other.

The phytogeographical connection of species of Campylopus in South America and Africa is also expressed by subspecies and species pairs (Frahm, 1988). For example, C. julaceus and C. trachyblepharon are both represented in SE Bra- zil and in SE Africa by subspecies differing only in the height of the dorsal lamellae of the costa or the presence of ventral hyalocysts or stereids in the transverse section of the costa (Frahm, 1985a). Both subspecies occur not only at the same latitude on the east coasts of the respective continents, but also in the same habitats of nu- trient poor sand near sea level. The same disjunction between SE Brazil and Malagasy is found in the hepatic genus Bryopteris and the moss genus Phyllogonium. A similar effect is that of species pairs occurring in both continents as Cam- pylopus sehnemii and C. controversus in South America and C. cataractilis and C. stenopelma in South Africa (although there is principally no difference since the differentiation between subspecies and species pairs is surely problematical). Both species pairs are so closely related that a common origin of both species is most probable. It can be supposed that both species are derived from subantarctic ancestors, which are still ex- tant (C. incrassatus for C. sehnemii/cataractilis and C. purpureocaulis for C. controversus/stenopelma). After continental separation, both species may have migrated northwards to the subtropical and tropical regions and in this way have developed their own characters.

Disjunctions between Central America and Asia are illustrated by Campylopus japonicus (Mexico-Japan) and Brothera leana (East Asia- SE North and Central America). This is a type of disjunction found more frequently in other bryophytes as a result of a previous circumpacific range in the Tertiary. The genus Campylopo- diella is also disjunct between Asia and the neotropics with C. himalayana and C. crenulata in the Himalayas and New Guinea and C. stenocarpa and C. flagellacea in Central America and the Andes.

A circum-Tethyan range is found in Campy- lopus oerstedianus, occurring in Costa Rica, Ja- maica, Georgia and again in scattered localities in southern Europe. This indicates a Mesozoic age of this species, the scattered present distribution being a result of the lack of sporophytes and probably also unfavorable ecological conditions.

A disjunction between North and South Amer- ica is found in Campylopus carolinae which is found in the Cerrado regions of Brazil and also in the alluvial coastal plains of Florida, Georgia and the Carolinas. In both regions absolutely the same habitat is occupied (white sand in often burned vegetation in which the minute plants are buried). Campylopus surinamensis also grows on white sand and shows a similar distribution pattern but occurs also in between in the Amazon lowland. Campylopus angustiretis is disjunct between SE Brazil and the Caribbean and is found in the same vegetation types as the previous species, but in swampy places. All three species can be regarded as relicts of a former continuous range of a dry vegetation type linking Brazil, the Ca- ribbean and the SE of North America. In contrast, the occurrence of C. trachyblepharon (which grows in coastal sand and is mainly distributed in SE Brazil) in N Brazil and the Bermudas is interpreted rather as a result of dispersal by birds.

Only few species show pan-neotropic ranges and are found from Central America to Brazil (but usually with the exception of the Amazon lowland). This concerns Microcampylopus curvisetus, Pilopogon gracilis, Bryohumbertiafilifolia, Campylopus lamellinervis and C. subcuspidatus (except for the Andes), C. richardii, and C. arctocarpus and in addition the lowland and montane species with an African-South American disjunction such as Campylopus fragilis, C. flexuosus, C. savannarum, and C. pilifer. Also, Bryo-


20 Flora Neotropica

humbertia filifolia and Campylopus arctocarpus have close relations to Africa, as indicated by the fact that B. filifolia is replaced in Africa by a closely related species, B. metzlerelloides, and C. arctocarpus is replaced by a vicariant race, ssp. madecassus.

Within South America disjunctions can be observed between the Andes and SE Brazil. There are several categories of species: species which show no differences between the populations (Atractylocarpus longisetus, Campylopus cuspi- datus, C. heterostachys, C. jamesonii, C. densi- coma, C. reflexisetus); populations, as in Pilo- pogon gracilis, in which differences can be stated numerically, but which, however, overlap and do not allow separation of these populations tax- onomically (Frahm, 1983a); subspecies, as in Campylopus fragilis subsp. fragilis in the Andes and subsp. fragiliformis in SE Brazil; or geographical vicariant species such as Atractylocar- pus brasiliensis and A. longisetus or A. nanus. These disjunctions can be explained either by long distance dispersal or as relicts of a formerly closed range that included the Andes and the SE Brazilian mountains in a presumably cooler climatic period.

Extensions of boreal ranges to Central Amer- ica, rarely to South America, are found only in Paraleucobryum enerve and Dicranodontium denudatum.

Disjunctions between Central America and SE North America are demonstrated by Brothera leana and Campylopus tallulensis.

Campylopus shawii is disjunct in the Carib- bean, the Azores and the British Isles.

Several species are endemic to SE Brazil, for example Campylopus cryptopodioides, C. di- chrostis, C. gemmatus, C. julicaulis, C. uleanus and C. viridatus. Some Campylopus species (C. aemulans, C. julaceus, C. griseus and C. occultus) are also found on or proceed to the slopes of the Andes in N Argentina and S Bolivia.

Campylopus gardneri, C. gastro-alaris and C. widgrenii are endemic to the arid parts of S and NE Brazil.

There are numerous species which are confined to the Andes and which have probably evolved in consequence of the uplift of these mountains at the end of Tertiary. This makes the Andes the region with the highest number of species in the world for Campylopus and Pilo- pogon. According to the humidity gradient in the

Andes from the Equator north and south the ranges of these species are very different. The widest ranges from Mexico to Bolivia (rarely to northern Argentina) are found in Campylopus albidovirens, C. anderssonii, C. concolor, C. ob- longus, C. pittieri, C. sharpii and C. zygodonticarpus. Species confined to the region between Costa Rica and Peru or northern Bolivia are Campylopus asperifolius, C. cavifolius, C. huallagensis, C. trivialis and Pilopogon laevis. Only found between Venezuela and Bolivia (and often confined to even smaller ranges such as Colom- bia to Peru or Colombia and Venezuela) and not in Central America are Atractylocarpus nanus, Campylopus amboroensis, C. areodictyon, C. argyrocaulon, C. bryotropii, C. capitulatus, C. clee- fii, C. edithae, C. incertus, C. jugorum, C. lon- gicellularis, C. luteus, C. perexilis, C. subjugorum, C. trichophylloides, Pilopogon peruvianus and P. macrocarpus. These are predominantly alpine species. Some species have even smaller ranges, e.g., confined to Bolivia (P. tiquipayae) or Co- lombia (Sphaerothecium phascoideum). The only species confined to Central America seems to be Dicranodontium meridionale, but this genus has not yet been monographed and therefore any phytogeographical interpretations are doubtful.

A phytogeographical discussion for the species of Campylopus and Bryohumbertia from the Ro- raima massif is given by Frahm and Gradstein (1987).

Campylopus cygneus and C. cubensis are confined to the Caribbean, the latter is also found in the surrounding parts of the continent in Cen- tral and northern South America, perhaps as a result of secondary spreading.

ORIGIN AND EVOLUTION Because of the lack of any fossils from either

subfamily, only speculations can be given derived from interpretation of the present ranges of species and genera.

Atractylocarpus is represented in nearly all mountain massifs of the world, each with a single species. Since these mountains are predominantly of Tertiary Age, speciation within this genus has happened presumably only during the last 50 million years. Atractylocarpus is mainly tropical and alpine in distribution. It is closely related to Dicranodontium, which is boreal and montane. The anatomical differences concern


Origin and Evolution21

mainly the sinuose or erect setae. A circumboreal distribution can go back to a Laurasian origin and thus it can be assumed that Dicranodontium is older than Atractylocarpus and that the latter has evolved from Dicranodontium by occupying new niches in alpine regions and has differentiated into several species on isolated mountain massifs.

In Campylopus it is notable that there are 15 (revised from 60 described) species in the subantarctic but only one in the subarctic. More- over, (except for one) only species with hyaline thin walled basal laminal cells occur in the subantarctic, and the most primitive representative of the subgenus Thysanomitrion also occurs there. So it can be assumed that this genus evolved in the southern part of the Gondwana continent. Presumably, a rich speciation took place (1) by isolation caused by continental drift, (2) by spreading northwards in the continents under more favorable climatic conditions, which were xeric in the preceding Mesozoic, (3) by adaptation to new habitats in savannas and rainforests and (4) by speciation in new mountain systems. For several groups of species, pathways can be constructed illustrating these mechanisms (Frahm, 1988). The existence of a circumtethyan relict (a conspicuously dry-adapted species with hairpoints) indicates that representatives of this genus were also present at the northern part of the Gondwana continent.

As shown by bud-like perichaetia on appressed foliate stalks and a different type of peristome, found also in the youngest species of Pilopogon and in certain species of the subg. Thysanomitri- on, (especially those occurring in SE Asia), the subg. Thysanomitrion may represent the youngest branch of evolution in this genus.

The close relationship between Campylopus and Dicranodontium leads to the suspicion that both genera (one in Gondwana, the other in Laurasia) have a common ancestor. Nearly all species of Dicranodontium can be distinguished from certain species of Campylopus only by elongate upper laminal cells. In contrast to Campy- lopus, Dicranodontium has never developed the large variety of different structures of the costa. It therefore has remained conservative and less flexible. Not able to adapt to different new habitats, the genus was not able to participate in an enormous speciation as was Campylopus. There- fore it remained confined to its former range and

did not spread substantially into the tropics. In a little known bryofloristic paper on the Austrian Alps, Loeske (1910) discussed relationships between genera of Dicranaceae. Based on the similarities in the structure of the costa and the lamina with Ditrichum, Loeske derived Campylopus and Dicranodontium from Ditrichaceae. Para- leucobryum belongs, according to Loeske, to the same evolutionary line. For that reason Loeske proposed to separate Campylopus, Dicranodon- tium and perhaps also Paraleucobryum from the Dicranaceae and to establish a new family, Cam- pylopodaceae.

Pilopogon also resembles certain species of Campylopus and can be distinguished only by the straight seta and the long perichaetial leaves. Six of the seven species occur in the Neotropics, five of them exclusively in the Andes. As indicated by the dicranoid type of the peristome in the only African species and the advanced type of peristome in the neotropical species, the genus originated in the Mesozoic before the split of the Gondwana continent but further evolved later in the Andes.

Bryohumbertia is again closely related to Cam- pylopus, differing by longer setae, a longer operculum and smooth peristome teeth. Three species are distinguished worldwide, one in each of the main tropical regions. The differences between these species are so small that certain small specimens can hardly be referred to one or the other of these species, whereas some large growth forms are confined to the neotropics. This close relationship indicates a common origin and a recent differentiation after the split of the continents which may have not yet reached a separation into fully separate species.

The three species of Spaherothecium found in Colombia, South Africa and Sri Lanka also show only small differences. The nearly worldwide distribution indicates an older age for the genus than Bryohumbertia, with a late or post Mesozoic speciation caused by isolation. The small ranges of all these species indicate that the present ecological conditions are not best for these species. Since these species grow on bare soil and not in shel- tered habitats, it may be speculated that these species (two of which are known only from the type collections made 130 years ago, a third known from only halfa dozen collections) cannot survive in such small populations and may be extinct in the future, if not now.


22 Flora Neotropica

Microcampylopus and Campylopodium differ mainly in the ornamentation of the spores and the presence or absence of stomata in the neck of the capsules. Consequently, both genera have a relation similar to that of Dicranella (stomata absent) and Anisothecium (stomata present), which are often united. A common origin for both genera can be assumed, perhaps derived from Anisothecium by development of the twisted and sinuose seta of the Campylopus-type or by sharing the same ancestor with Dicranella and Anisothecium. Microcampylopus is distributed pantropically, with one species each in South America, Africa and SE Asia. These species probably evolved after the separation of the continents and, because of their close relationship (the differences concern only length/width of the capsule and the spore ornamentation), are de- scendants of a Mesozoic ancestor. Campylopo- dium is SE Asian in distribution, with two species (the occurrence of C. medium in Chile is interpreted as a Pacific extension of this range), and therefore might have developed from Microcam- pylopus in this region, or is older, with formerly vicariant species in other parts of the tropics extinct. A third possibility might be that the Chil- ean and New Zealand occurrences are relicts of a gondwanalandic range and the occurrence of C. medium in SE Asia is a secondary extension.

ECOLOGY

SUBSTRATE

Most species of Campylopodioideae and Para- leucobryoideae grow on soil, rocks, decaying wood or tree bases. This is true for all genera except Campylopus and Pilopogon. Only a few species of the latter genera, occurring in the An- des and the mountains of SE Brazil, are epiphytes. This supports the hypothesis of a Gon- wanalandic origin and migration to the tropics, where only a few taxa adapted to this new habitat. Within the neotropics, only one Pilopogon species, P. longirostratus, is found as epiphyte. In Campylopus only a few species such as C. asperifolius occur on tree trunks or bamboo nodes. (Species growing also on stems of tree ferns cannot be taken into account here since they are not true epiphytes.) Only one species, Campylopus huallagensis var. weberbaueri from the Andes, has become a branch epiphyte.

For an unknown reason all species of Paraleu-

cobryoideae and Campylopodioideae (as most Dicranaceae) are strictly acidophytic and found only on substrates with a pH

Ecology23

ten pitted basal cell walls, which function for water storage (Biebl, 1964).

Resistance to Water Loss

Growth form plays an important role for resistance to water loss. Species of exposed habitats show dense tufts or cushions (as in high andine species such as Paraleucobryum enerve, Atrac- tylocarpus ssp., Campylopus nivalis, C. cavifolius, C. areodictyon, C. edithae, etc. The same concerns subantarctic species.

As in many other acrocarpous mosses a number of species of Campylopus have excurrent costae forming hyaline hairpoints, functioning as protection against strong radiation and desiccation. In some species these hairpoints vary de- pending on the habitat, as in Campylopus savannarum with a concolorous excurrent costa in rainforest habitats but a distinct hyaline excurrent costa in the "bartletti"' expression of dry cerrado habitats.

UPTAKE OF WATER AND NUTRIENTS

The anatomies of Paraleucobryoideae and Campylopodioideae show adaptions to a less developed internal and well developed external water conduction. A structure supporting endohy- dric water supply is the presence of a central stand in the stem. Ectohydric features are easily wetted surfaces of leaves which become turges- cent rapidly, no water repellent leaf surfaces, frequent presence of a rhizoid tomentum and hyaline leaf bases. However, there are no leaf papillae developed to spread water easily over the leaf surface; all species have totally smooth leaves.

SEXUAL REPRODUCTION

Sexual reproduction plays a different role in the genera treated here. Species of Microcam- pylopus and Campylopodium are nearly always found with sporophytes. In this respect these genera resemble Dicranella, to which they ultimately may be found more closely related than to the Campylopodioideae. For Sphaerothecium the rate of fertility cannot be estimated since the species are known from only a few collections. It can be assumed that specimens have been collected only with sporophytes, because the species can almost not be distinguished from other genera without

capsules. In Brothera there are numerous collections of fertile material from its Asian range. However, in North and Central America the species is found always sterile. In the neotropic species of Campylopodiella, C. flagellacea is nearly always sterile and has been found with sporophytes only once, but in contrast, C. stenocarpa is found usually fertile. Only a small number of species of Campylopus produce sporophytes frequently. In many species sporophytes are found only rarely, and again in many species no sporophytes are known. This is remarkable, inasmuch as Campylopus has developed this special turn and twist mechanism of the sporophytes for spore dispersal, which is, however, apparently not necessarily needed. In contrast to all other genera treated here, some species of Campylopus produce several sporophytes in one perichae- tium, usually 3-7. This is especially characteristic for colonists such as C. introflexus, C. richardii or C. occultus. But even closely related or geographically vicariant species can differ in spore production, like C. introflexus, met frequently with sporophytes, versus C. pilifer, which is rarely found with sporophytes. Dry-adapted species produce sporophytes more rarely than species of wet habitats, which apparently reflects better conditions for fertilization in wet habitats and better vegetative propagation in dry habitats.

Generally, species producing sporophytes have larger ranges. This is especially true of species with large disjunctions, such as between South America and Africa. Species in which sporophytes are not known have either small ranges or are known from few localities which also may be very scattered. An example is Campylopus oerstedianus, known from less than a dozen records in Costa Rica, Georgia and SW Europe.

The number of spores per capsule is not known in even a single genus. However, the spore size is about the same in all genera, with the exception of Microcampylopus and Campylopodium, which have spores of 18-24 ,um diameter and Sphaero- thecium with spores 21 ,m in diameter. There- fore, the size and number of capsules may give an impression of the fertility of the genera.

The duration for the sporophyte development is not known for tropical species. In temperate regions all genera show two growth periods a year, each with one sporophyte generation. The sporophyte development thus takes less than 6 months. The fertility in general seems to be higher in temperate and subtropical regions than in


24 Flora Neotropica

the innertropics. This may depend on the pho- toperiod in the sense that bryophytes usually re- quire long days for the development of sex organs.

VEGETATIVE REPRODUCTION

The total lack or rareness of sporophytes in many species shows that there exist effective methods for vegetative propagation.

The production of organs for vegetative propagation is usually seasonal and happens during a dry season, allowing a dispersal by wind, and a regrowth in the next humid season. Some populations produce propagules always, others never. Plants without propagules show optimal growth, the others not. Therefore, vegetative propagation may indicate ecological stress.

Although there are several different methods of vegetative propagation, a given method is usually but not entirely confined to certain taxa. For example, brood leaves are characteristic for C. fragilis and microphyllous branches for C. flexuosus. However, there have also been found (but extremely rarely) microphyllous branches in C. fragilis and brood leaves in C. flexuosus. This indicates that while all species may have the same faculties for all methods of vegetative propagation, they are, however, used differently.

Several species can switch between vegetative and generative propagation, which is a most successful response to balance alterations of habitats.

SYSTEMATIC TREATMENT

CAMPYLOPODIOIDEAE

Plants small, from a few mm to 15 cm high, yellowish green, light to dark green or olive to

almost blackish, in loose tufts. Stems erect, rarely branched, often tomentose in the lower part, comose at tips or not so, rarely verticillate foliate. Dioicous. Perichaetia terminal, rarely pseudolateral, surrounded by comose leaves; perichaetial leaves with broad sheathing base, abruptly contracted to subulae. Stem leaves lanceolate, erect spreading to appressed, sometimes homo- mallous or straight, ending in a fine denticulate, serrate or smooth, sometimes hyaline tip. Costae broad, filling 1/3 to 3/ of the leaf width, excurrent or nearly so, in transverse section with a median row of deuter cells, dorsal layers of a (sub)stereidal band and an epidermal layer and ventrally a single or multilayerred stereid band or a single row ofhyalocysts, the abaxial surface smooth, ribbed or lamellose; alar cells lacking, more or less developed or conspicuous, inflated or auriculate, reddish or hyaline; basal la

Flora Neotropica

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