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: pkverma_bryo@yahoo.co.in

K. K. Rawat

CSIR-National Botanical Research Institute, Rana Pratap Marg,

Lucknow 226 001, Uttar Pradesh, India

e-mail: drkkrawat@rediffmail.com

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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