RESEARCH ARTICLE
Anthoceros subtilis Steph: A Rare Disjunct Species, New to NorthEast India from Brahmaputra Valley
Praveen Kumar Verma • Krishna Kumar Rawat •
Ranjeet Kumar
Received: 4 June 2013 / Revised: 13 November 2013 / Accepted: 16 December 2013
� The National Academy of Sciences, India 2014
Abstract A rare bryophyte, Anthoceros subtilis Steph.,
earlier reported in India only from Western Ghats, (Kar-
nataka and Maharashtra), Gujarat, Rajasthan and elsewhere
in world from China, Thailand and Vietnam, has been
discovered from southern Brahmaputra flood plains of
Assam.
Keywords Bryophyta � Anthoceros � Assam �Brahmaputra flood plain � Disjunct distribution
Introduction
Disjunct distributions among different bio-geographic
zones of the different continents have intrigued bryologist
for decades. The bryophytes produce spores or specialized
propagules and unspecialised gametophyte fragments,
which disperse over long distances by wind, water or by other
artificial means [1]. This type of air-borne dissemination
sometimes produces remarkable disjunction in distribution
pattern [2] ranging from regional to transcontinental, trans-
oceanic or may be polar disjunction.
Hornworts differ from other bryophytes in having a horn-
shaped sporophyte which continues to grow at the base as
spores mature and are dispersed at the apex. This is one of
the least species-rich bryophyte group with about 200–250
species across the world. The group has rather fascinated
scientists because of their unique combination of morpho-
logical and developmental traits [3]. Hornworts belong to a
comparatively small ancient group of embryophytes known
through spores since Cretaceous [4]. Presently there are 14
genera of hornworts worldwide viz., Anthoceros L., Dend-
roceros Nees, Folioceros D. C. Bharadwaj, Hattorioceros
(Hasegawa) Hasegawa, Leiosporoceros Hassel, Megaceros
Campb., Mesoceros Piippo, Notothylas Sull. ex A. Gray,
Nothoceros (R. M. Schuster) Hasegawa, Paraphymatoceros
Hassel, Phaeoceros Prosk., Phaeomegaceros Duff et al.,
Phymatoceros Stotler, W. T. Doyle and Crand.-Stotl. and
Sphaerosporoceros Hassel. Out of them Anthoceros,
Dendroceros, Folioceros, Hattorioceros, Megaceros, Not-
othylas and Phaeoceros are found in India. The country is
also credited for the discovery of two genera Folioceros
from Assam and Hattorioceros from Himachal Pradesh [3,
5–7].
Genus Anthoceros is characterized by the presence of
nitrogen fixer cyanophycean alga Nostoc and is commonly
found in tropical and subtropical countries, and often in
temperate areas. Asthana and Srivastava [8] reported nine
species of Anthoceros from India viz. A. alpinus Steph.,
A. angustus Steph., A. bharadwajii Udar and Asthana,
A. crispulus (Montagne.) Douin., A. erectus Kashyap, A.
macrospores Steph., A. pandei Udar and Asthana, A.
punctatus L. and A. subtilis Steph.
This study focuses on Anthoceros subtilis Steph., a
remarkable hornwort species, reported herewith for the first
time from southern Brahmaputra flood plain of Assam
(Jorhat) in north-east India. It shows a regionally disjunct
distribution pattern which is particularly pronounced in
case of a number of Indo-Himalayan or Sino-Himalayan
elements of the peninsular Indian biota.
P. K. Verma (&) � R. Kumar
Shifting Cultivation Division, Rain Forest Research Institute,
Deovan, Sotai Ali, Post Box 136, Jorhat 785 001, Assam, India
e-mail: [email protected]
K. K. Rawat
CSIR-National Botanical Research Institute, Rana Pratap Marg,
Lucknow 226 001, Uttar Pradesh, India
e-mail: [email protected]
123
Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci.
DOI 10.1007/s40011-013-0289-0
Material and Methods
The plants were collected from different localities of Jorhat
district of Assam during various collection trips from
December 2012 to March, 2013 and deposited in herbarium
RFRI. The plants were found growing in large compact
patches.
Taxonomic Treatment
Anthoceros subtilis Steph., Spec. Hepat. 5: 1003, 1916
(Fig. 1–6).
Type: India: Karnataka-South Kanara (Mangalore), R.
Pfleiderer, 12823, Aug., 1907 (G).
Plant diecious, male plants not seen. Female plants in
compact patches forming rosettes, dark green, 2–3 cm
across (Fig. 1.1, 1.2), look very frilly, and usually have
various ridges and crests on the upper surface., 8–12 mm in
diameter, margin deeply dissected and appeared as puffy,
thallus containing mucilage schizogenous cavities in a
single row, mucilage opaque; intermixed with cyanophy-
cean algae embedded in thallus, epidermal cells consist of
single large light chloroplast with single pyrenoid. Invo-
lucers soft, 4–12 per plant, up to 4–6 mm long; sporophyte
long, with 20–30 stomata per mm2 on outer wall of capsule
wall. Spore dark brown, 40–53 lm in diameter, with blunt
spinulate–baculate projections, often notched, distal face
spinulated compactly (Fig. 1.3), proximal end clearly tri-
radiated (Fig. 1.4), tri-radiate mark reaching up to periph-
ery; pseudo-elaters light brown, variously shaped thin, 2–4
celled, often stumpy (Fig. 1.5, 1.6).
Specimens Examined
India: ASSAM: Jorhat-Bhagdoi river, C. 116 m;
15.12.2012; P. K. Verma, 312/2012, 313/2012 (RFRI);
Jorhat-Rain Forest Research Institute nursery; C. 115 m;
20.01.2013; P. K. Verma; 328/2013, 329/2013, 330/2013
(RFRI); Jorhat-South bank of Brahmaputra near Jajimukh;
C. 105 m; 28.02.2013; P. K. Verma, 331/2013 (RFRI).
Habitat
Mainly at wet and shady places, bamboo nursery, crop field
often intermixed with Marchantia and Riccia sp. forming
large patches.
Distribution Range
China [9], Thailand [10], Vietnam (as A. fuscus) [8], India-
Gujarat [11], Karnataka [8], Kerala [12], Maharashtra [8],
Rajasthan [13] and Assam (Jorhat, Present report, new
addition to East Himalayan flora).
Fig. 1–6 Anthoceros subtilis
Steph. 1 Habit and morphology,
2 same magnified. 3 distal view
of spore. 4 proximal view of
spores. 5, 6 pseudoelaters (Bars
1 = 4 cm, 2 = 2 cm, 3–4 =
50 lm, 5 = 215 lm, 6 =
360 lm), all photographs taken
from 328/2013
P. K. Verma et al.
123
Results and Discussion
In India, A. subtilis was first reported by Stephani [14] from
peninsular India on the basis of collection of Pfleiderer.
Asthana and Srivastava [8] synonymised, A. fuscus Steph.
of Vietnam and A. notothyloides from Mangalore under A.
subtilis, thus reporting presence of this species in two
widely disconnected regions viz. south India and south-east
Asia [8–10]. Subsequently this species has also been
reported from some localities of west India including Ra-
jasthan and Gujarat [12, 13].The present addition of the
species from southern bank of Brahmaputra flood plain is
quite interesting as the area is geographically isolated from
Indian mainland territory due to vast expanse of mighty
Brahmaputra. Being a subcontinent, any widely discon-
nected distributed pattern in the country, like the one
herewith in case of A. subtilis, cannot be simply treated as
long range dispersal. Instead it may be considered as a
regional disjunction. Same distribution pattern can be
observed in many other liverwort elements distributed in
eastern Himalaya and Western Ghats, two biodiversity hot
spots with high number of endemic elements. Karanth [15]
has discussed in details the disjunction of wet zone areas
particularly southwest India and northeast India and sub-
sequently disjunction among the wet zone taxa of the
Indian subcontinent. He emphasized that now separated by
a dry zone of central India, the wet zone was earlier present
in the form of a continuous tropical evergreen forest area
from northeast India to south India through Vindhya-Sat-
pura/Aravali/Eastern Ghats corridors. Hence it may be
possible that the current disjunction of a taxa might be a
relic of the former continuous distribution [15]. The same
may have happened here also in case of A. subtilis. Karanth
[15] has also considered the establishment of a dry zone
and subsequent cut off of wet zone species by this dry zone.
However, at this stage, it is difficult to say that whether this
type of disjunction particularly in case of A. subtilis is the
result of fragmentation of once large population or a totally
independent dispersal through different routes, which
needs further studies for confirmation.
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Anthoceros subtilis Steph: A Rare Disjunct Species
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