Journal of Threatened Taxa | www.threatenedtaxa.org | 26 September 2021 | 13(11): 19645–19648

 

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) 

https://doi.org/10.11609/jott.7459.13.11.19645-19648

#7459 | Received 22 May 2021 | Final received 12 August 2021 | Finally accepted 16 August 2021

 

 

Dryopteris lunanensis (Dryopteridaceae) - an addition to the pteridophytic diversity of India

 

Chhandam Chanda 1, Christopher Roy Fraser-Jenkins 2 & Vineet Kumar Rawat 3

 

1,3 Botanical Survey of India, Arunachal Pradesh Regional Centre, Senki View, Itanagar, Arunachal Pradesh 791111, India.

2 Rua de São Mateus 485 S/C Dt., Fontainhas 2750-141, Cascais, Portugal.

1 chhandambangali@yahoo.com (corresponding author), 2 chrisophilus@yahoo.co.uk, 3 rawat_vk2107@rediffmail.com

 

 

Editor: Anonymity requested.   Date of publication: 26 Septtember 2021 (online & print)

 

Citation: Chanda, C., C.R. Fraser-Jenkins & V.K. Rawat (2021). Dryopteris lunanensis (Dryopteridaceae) - an addition to the pteridophytic diversity of India.  Journal of Threatened Taxa 13(11): 19645–19648. https://doi.org/10.11609/jott.7459.13.11.19645-19648

 

Copyright: © Chanda et al. 2021. Creative Commons Attribution 4.0 International License.  JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

 

Funding: Botanical Survey of India.

 

Competing interests: The authors declare no competing interests.

 

Acknowledgements: The authors are grateful to Dr. A.A. Mao, Director of the Botanical Suvey of India, for providing all necessary logistical support.  We are also grateful to the Department of the Environment and Forests. Government of Arunachal Pradesh, for providing necessary permits and facilities for our field-survey. We also acknowledge the field-assistance of Mr. Rohan Maity, Junior Project Fellow, Arunachal Pradesh Regional Centre, Botanical Survey of India,  We gratefully acknowledge access to the website data-bases of the following herbaria BM, K, P and CAL.

 

 

 

Abstract: The occurrence of the very rare and little-known fern, Dryopteris lunanensis (Christ) C.Chr., in India is reported for the first time. A detailed description and photographs of the species are provided along with notes on its distribution. A second-step lectotype has also been designated.

 

Keywords: Arunachal Pradesh, distribution, fern, Pteridophyta.

 

 

The genus Dryopteris Adans. (Dryopteridaceae) is one of the most widespread fern genera with approximately 350 species worldwide (Fraser-Jenkins 1986; POWO 2021) and has high species diversity in subtropical montane regions, though the genus extends northwards into boreal regions as well. The Sino-Himalayan and Sino-Japanese regions support the greatest numerical and morphological diversity, with secondary centres of diversity in Africa, Europe (including Macronesia), Hawai’I, and North America. Dryopteris in India is represented by 66 species and seven hybrids (Fraser-Jenkins 1989; Fraser-Jenkins et al. 2018), excluding the distinct Dryopteridaceous genera, Peranema, Nothoperanema, and Dryopsis, in contrast to a recent cladonomic oversimplification by Zhang (2012) and Zhang & Zhang (2012) artificially intended to avoid paraphyly. Many species have been discovered recently in the eastern Indo-Himalaya that were previously only known from the main centre of distribution in southeastern Tibet and southwestern China.  Of these, Dryopteris lunanensis (Christ) C.Chr., a distinctive species in Sect. Hirtipedes, was detailed from a single collection in Bhutan by Fraser-Jenkins (1989), now augmented by a second Bhutanese collection, but was not previously collected in India.

A misidentification of supposed D. lunanensis from India was made by S.R. Ghosh concerning a specimen from Ukhrul, Manipur (R.D. Dixit 58874, 24.2.1987, CAL!), but the specimen was unequivocally reidentified by Fraser-Jenkins et al. (2018) as D. scottii Ching, a very different species. 

The first author recently collected a specimen from Dibang Wildlife Sanctuary, Arunachal Pradesh. After critically observing its morphological characters, it was immediately identified as D. lunanensis by the second author from his familiarity with collections of the species in China and Bhutan. This is therefore the first authentic report of this species from India. Its taxonomy and distribution, along with photographs are provided here. A second-step lectotype is also designated in the present article in accordance with its lectotypification by Fraser-Jenkins (1989) and the ICN (Turland et al. 2018). 

Methods and Materials: During the field-survey in Dibang Wildlife Sanctuary of Arunachal Pradesh, a few specimens of an unusual Dryopteris were collected. The collected specimens were not immediately able to be identified and after preparation as herbarium-specimens were photographed and the photographs were sent to the second author, who identified them as Dryopteris lunanensis (Christ) C.Chr.  The collection showed the typical long, sparsely scaly stipe with darkish brown scales, deeply lobed pinnae (to just over half way to the rachis on each side) with slightly narrowed bases, slightly falcate-deflexed lowest pinnae and aristate and slightly flabellate teeth at the lobe-apices (Ching 1938; Fraser-Jenkins 1989). The specimen was deposited in ARUN herbarium, Itanagar.   

 

Dryopteris lunanensis (Christ) C.Chr., Index Filic.: 276. 1905.

Basionym: Aspidium lunanense Christ, Bull. Herb. Boissier 6: 966. 1898.

Type: (Lectotype (Fraser-Jenkins 1989), second-step, here designated): China, Yunnan, Lunan, A. Henry 10584, sin. date, P (P01514061 digital image!); Isolectotypes: BM (BM001066079 digital image!); K (K001080923 digital image!)

Synonyms: Dryopteris paralunanensis W.M.Chu ex S.G.Lu, Guihaia 11(3): 225. 1991.

Dryopteris semipinnata Ching, Fl. Tsinling. 2: 226. 1974. 

Description: Plant up to 60 cm tall. Rhizome short, thick, erect, scaly at the apex. Fronds bipinnatifid, arching, stipe nearly as long as the lamina, 20–30 cm, brown at base, stramineous upwards, dorsally grooved, densely scaly at base with scales 8–15 × 0.5–1 mm, blackish-brown, basifixed, narrowly lanceolate, base broad, margin ciliate, apex attenuated, sparsely scaly, with shorter, narrower scales, upwards and on the rachis; rachis stramineous, ± sparsely scaly;  lamina deltate-lanceolate,  subcoriaceous or slightly crispaceous, 25–30 × 10–15 cm; pinnae pinnatifid, lobed up to 2/3 towards costa or more, lanceolate, alternate, sessile to sub-sessile, apex acute to acuminate, 12–15 × 2–2.5 cm, characteristically narrowed at their bases; costae stramineous, sparsely scaly with small fibrils or hair-like scales, dorsally grooved; pinna-lobes with entire margins and rounded, acutely dentate apices, the teeth abruptly narrowed to their apices and slightly flabellate; veins simple, free. Sori indusiate, round, median, in two rows, one on each side of the midvein; indusia reniform, c. 0.5 mm in diameter.

Habitat: A terrestrial species, occurring at approximately 1,900 m altitude, in forest on slopes by streams.

Distribution: India (Arunachal Pradesh); Bhutan, China (Yunnan, Kweichow, Szechuan, Hunan, Kansu), Tibet, Japan.  Its long-known presence in Bhutan was mistakenly omitted by Wu et al. (2013) in the Flora of China.

Specimen examined: India, Arunachal Pradesh, Dibang Valley District, Dibang Wildlife Sanctuary, slope above streams in forest, c. 1900 m, C. Chanda 42060, 23.xi.2018, ARUN.

Conservation status: CR (Critically Endangered and known only from a single collection in India). Despite extensive collection by pteridologists in Arunachal Pradesh and elsewhere in northeastern India this distinctive and easily recognisable species has only been found as a single small group of a few individual plants in one locality.

Note: This species is rare and restricted in distribution throughout all parts of its range and is to be considered as globally threatened. It has only been collected twice before in the Indian subcontinent, both from west-central Bhutan (Punakha Dzongkhag, Tinlegang to Gon Chungnang, c. 1,700 m,  H. Kanai, G. Murata, H. Ohashi, O. Tanaka & T. Yamazaki 14832, 5.v.1967 (BM, TI, KYO) and Wangdue Phodrang Dzongkhag, Pho Chu, north-east of Kewa Nang, evergreen Quercus forest on steep E.-facing rock slope, undisturbed, 2,350 m, S. Miehe & D.B. Gurung 00-459-12, 10.xii.2000 (UC), det. CRFJ) (Fraser-Jenkins 1989 and in prep., re Bhutan). The present collection from India was made from an isolated group of only three individuals in a small area.

Nomenclatural Notes: Christ (1898) described Aspidium lunanense Christ on the basis of a specimen collected from Lunan (the “stone forest”), in Yunnan Province, China, A. Henry 10584. Christ mentioned in the first part of his paper that it concerned the collections of Augustine Henry from the Meng-tse (or Mong Tseu., now Mengzi) semi-autonomous area in southeastern Yunnan Province, situated south of Kunming and east of central Myanmar, north of Vietnam.

Referring to website data-bases, we found three specimens in BM, K and P (1 in each) and Fraser-Jenkins (1989) had also found a second specimen in P with the same details as provided in the protologue of A. lunanense. The specimens in K and P are well preserved and exhibit all the characters required for identification, while the specimen housed in BM has original circumscription copied and written by Christensen, but is only a single pinna taken by him from the Paris material and forming part of Christensen’s comprehensive type-fragment herbarium. The sheet at P, barcoded as P01514061 (digital image!), bears original data by Henry and “Aspidium lunanense n. sp. [species nova]” in Christ’s handwriting. We designate this sheet as a second-step lectotype.

 

For image - - click here

 

References

 

Ching, R.C. (1938). A revision of Chinese and Sikkim Himalayan Dryopteris, with reference to some species from neighbouring regions. Bulletin of the Fan Memorial Institute of Biology; Botany 8(6): 363–507.

Christ, H. (1898). Fougères de Mengtze, Yunnan Méridional (Chine). Bulletin de l’Herbier Boissier 6(11): 966.

Fraser-Jenkins, C.R. (1986). A classification of the genus Dryopteris (Pteridophyta, Dryopteridaceae). Bulletin of the British Museum (Natural History) Botany 14(3): 183–218.

Fraser-Jenkins, C.R. (1989).  A monograph of Dryopteris (Pteridophyta: Dryopteridaceae) in the Indian Subcontinent. Bulletin of the British Museum (Natural History) Botany 18(5): 323–477.

Fraser-Jenkins, C.R., K.N. Gandhi & B.S. Kholia (2018). An Annotated Checklist of Indian Pteridophytes, Part-2 (Woodsiaceae to Dryopteridaceae). Bishen Singh Mahendra Pal Singh, Dehra Dun, 287pp.

POWO (2021). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on-line: https://www.plantsoftheworldonline.org/  (accessed 12 January 2021).

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Wu, S.G., J.Y. Xiang, S.G. Lu, F.G. Wang, F.W. Xing, S.Y. Dong, H. He, L.-B. Zhang, D.S. Barrington & M.J.M. Christenhusz (2013). Dryopteris, pp. 575–602. In: Wu, Z.G., P.H. Raven & D.Y. Hong (eds.). Flora of China 2–3.  Science Press, Beijing and Missouri Botanical Garden, St Louis.

Zhang, L.-B. (2012). Reducing the fern genus Dryopsis to Dryopteris and the systematics and nomenclature of Dryopteris subgenus Erythrovariae section Dryopsis (Dryopteridaceae). Phytotaxa 71: 17–27.

Zhang, L.B. & L. Zhang (2012). The inclusion of Acrophorus, Diacalpe, Nothoperanema and Peranema in Dryopteris: The molecular phylogeny, systematics, and nomenclature of Dryopteris subg. Nothoperanema (Dryopteridaceae). Taxon 61(6): 1199–1216.