Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2026 | 18(8): 29555–29558

 

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

https://doi.org/10.11609/jott.9697.18.8.29555-29558

#9697 | Received 19 February 2025 | Final received 16 June 2026| Finally accepted 14 July 2026

 

 

Addition of Athyrium rhachidosorum (Hand.-Mazz.) Ching, 1934 (Polypodiales: Woodsiaceae) to the pteridophyte diversity of India

 

Chhandam Chanda 1   & Christopher Roy Fraser-Jenkins 2       

 

1 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 chhandambotany@gmail.com (corresponding author), 2 chrisophilus@yahoo.co.uk

 

 

Editor: Anonymity requested.           Date of publication: 26 August 2026 (online & print)

 

Citation: Chanda, C. & C.R. Fraser-Jenkins (2026). Addition of Athyrium rhachidosorum (Hand.-Mazz.) Ching, 1934 (Polypodiales: Woodsiaceae) to the pteridophyte diversity of India. Journal of Threatened Taxa 18(8): 29555–29558. https://doi.org/10.11609/jott.9697.18.8.29555-29558

  

Copyright: © Chanda & Fraser-Jenkins 2026. 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: The study was funded by The Ministry of Environment, Forest & Climate Change, Government of India.

 

Competing interests: The authors declare no competing interests.

 

Acknowledgements: The authors are grateful to Dr. A.A. Mao, director, Botanical Survey of India, for providing necessary logistical support. We are also grateful to the Department of Environment and Forests, Government of Arunachal Pradesh, for providing necessary permission. We thank Emudu Trekkers of Anini for assistance in survey work and exploration. We also acknowledge the cooperation of Mr. Rohan Maity, senior preservation assistant, Botanical Survey of India, during this work.

 

 

Athyrium Roth is a large and complex pteridophyte genus with many taxonomically critical species. This genus has been assigned to a separate family Athyriaceae (PPG I 2016). We here consider it to be under the family Woodsiaceae (Fraser-Jenkins 2008; Fraser-Jenkins et al. 2018). A total of 50 species and 17 hybrids of Athyrium were reported to occur in India in 2018 (Fraser-Jenkins et al. 2018), whereas in Arunachal Pradesh, 28 species of Athyrium were reported to occur (Chanda et al. 2024).

A. rhachidosorum was first reported from Myanmar but predominantly occur in China. So far, it was known to occur from these two countries only. The present paper reports the occurrence of A. rhachidosorum in India.

The species was collected from forest of Dibang Wildlife Sanctuary of Dibang Valley District of Arunachal Pradesh. It was found to grow in a subtemperate forest with lavish vegetation, in a high-altitude area (2,800 m). This forest is on the way to ‘Seven Lake’ area inside the Wildlife Sanctuary.

Collection: Several field survey tours were undertaken by the first author in Dibang Wildlife Sanctuary for the ‘Flora of India’ project, titled ‘Ferns and Fern-allies of Dihang-Dibang Biosphere Reserve of Arunachal Pradesh’. A. rhachidosorum was collected along with many other ferns during those field trips (Image 1).

Identification: The specimens were dried and mounted on herbarium sheets following the standard methods. Later, these were scanned with an Epson scanner, studied under a stereo microscope and photographed. During the process of identification of the collected specimens, the first author misidentified it to be Athyrium pectinatum. Later on, the second author identified it as A. rhachidosorum.

 

Athyrium rhachidosorum (Hand.-Mazz.) Ching, Index Filic. (C.Chr.), Suppl. Tert. 43. 1934 (as ‘rhachidisorum’) (Image 2).

Holotype: Northwestern Yunnan: in rainforest of the Burmese monastery in the valley below the Gomba-la Pass, in the Salwin-Irrawaddy catchment above Tschamutong, granite, 2,900 m, H. Handel-Mazzetti 4595, 12.vii.1916 (Wang et al. 2013).

Basionym: Asplenium rhachidosorum Hand.-Mazz., Symb. Sin. 6: 33. 1929.

Synonyms: Athyrium densisorum X.C.Zhang, Bull. Bot. Res., Harbin 11(3): 8. 1991.

Athyrium wuliangshanense Ching, Acta Bot. Boreal.-Occid. Sin. 6: 15. 1986.                 

Description: Rhizome erect, scaly. Fronds tufted, tripinnate to quadripinnatifid; stipe brown, scaly at lower half, dorsally grooved, 37–45 × 0.35–0.4 cm; scales dark brown with a pale brown margin, basifixed, lanceolate to ovate-lanceolate, base truncate, margin entire, apex acuminate to caudate, 3–6 × 1–2 mm; rachis stramineous, glabrous; lamina oblong-lanceolate, herbaceous, 40–45 cm × 15–18 cm; pinnae bipinnate to tripinnatifid, subopposite to alternate, stalked, triangular-lanceolate, apex caudate, 7–18 × 1.7–4 cm, lower 2 pairs slightly shorter; costae stramineous, often very narrowly winged; pinnules pinnate to bipinnatifid, subopposite to alternate, stalked, lanceolate, asymmetrical with slightly larger acroscopic pinnulets, base truncate acroscopically and cuneate basiscopically, apex obtuse to acute, with minute dentation, 1–2.5 × 0.35–0.6 cm, few pairs of lower pinnules in lower pinnae gradually shortened; costules with 2–3 short setae; pinnulets simple to pinnatifid, alternate, sessile, oblong-lanceolate, anadromous, base adnate, margin entire to lobed, apex obtuse, dentate, 2–4 × 1–1.5 mm, basal acroscopic one largest; ultimate lobes linear, apex obtuse to acute, up to 2 × 0.7 mm; veins inconspicuous, forked, free. Sori oblong, indusiate, central, one at the base of each pinnulet; indusia thin; spores brown, monolete, reniform, surface irregularly tuberculate, perispore absent, 38–42 × 25–28 μm (Image 2).

Note: This species can be circumscribed by the following characters – erect rhizome; tripinnate to quadripinnatifid fronds; oblong-lanceolate lamina with slightly shorter basal pairs of pinnae; asymmetrical pinnule bases; slightly larger acroscopic pinnulets than basiscopic ones; linear ultimate segments; 2–3 setae on costules and centrally arranged, oblong sori.

Habitat: A very rare, high-altitude, terrestrial species, growing on forest floor, in dense forests.

Distribution: India (Arunachal Pradesh), China (Sichuan, Xizang, & Yunnan), and Myanmar (Flora of China 2013).

Specimen examined: India, Arunachal Pradesh, Dibang Valley, Dibang Wildlife Sanctuary, north-east of Emuli Village, towards 2nd camp, c. 2,800 m, 17.xi.2021, C. Chanda 43661, ARUN (Image 3).

 

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References

 

Chanda, C. et al. (2024). The genus Athyrium in Arunachal Pradesh state, India. Phytotaxa 636(4): 262–278. https://doi.org/10.11646/phytotaxa.636.4.1

Fraser-Jenkins, C.R. (2008). Taxonomic Revision of Three Hundred Indian Subcontinental Pteridophytes with a Revised Census-list. Bishen Singh Mahendra Pal Singh, Dehra Dun, 685 pp.

Fraser-Jenkins, C.R. et al. (2018). An Annotated Checklist of Indian Pteridophytes, Part-2. Bishen Singh Mahendra Pal Singh, Dehra Dun, 573 pp.

Schuettpelz, E. & H. Schneider (PPG I) (2016). A community-derived classification for extanlycophytes and ferns. Journal of Systematics and Evolution 54(6): 563–603. https://doi.org/10.1111/jse.12229

Wang, Z. et al. (2013). Athyriaceae. In: Wu, Z.Y. et al. (eds.). Flora of China, Volume 20–21.