The genus Neottia Guettard (1754) (Guettard 1754) [Orchidaceae-Epidendroideae-Neottieae] was initially represented by its mycoheterotrophic members, whereas Listera Brown (1813) (Brown 1813) was represented only by autotrophic species. Later, Szlachetko (1995) recognized three subgenera, viz. Archineottia Chen (1979) Chen (1979), Listera, and Neottia under the genus Neottia. Chase et al. (2003) considered Listera as the photosynthetic members of Neottia and suggested that both the genera Listera and Neottia should be treated as the same genus based on DNA studies. Neottia has the priority, as it is the oldest name. The genus Neottia is characterized by its small habit, dense fibrous or fleshy roots, small resupinate flowers, often bilobed ligulate labellum, mostly long and curved column, sectile and naked pollinia (Pridgeon et al. 2005; Chen & Jin 2021). The genus comprises 64 species worldwide (Chase et al. 2015), distributed in the Himalayas, the Northern Temperate Zone, and south to tropical mainland Asia and the adjacent islands (Pridgeon et al. 2005). In India, the genus is represented by 20 species distributed exclusively in the Himalayan region (Singh et al. 2019; Kumar & Kumar 2024).

Wen et al. (2024) described a new species, Neottia ‌motuoensis ‌X.H.Jin, based on the specimens collected from Motuo County, Xizang, China. While describing N. ‌motuoensis, the authors (Wen et al. 2024) compared their species with N. ‌yunnanensis ‌(S.C.Chen) Szlach., but they overlooked N. ‌alternifolia ‌(King & Pantl.) Szlach. (basionym: Listera ‌alternifolia ‌King & Pantl.), which was also reported from China (Jin et al. 2014; Zhou et al. 2016). After a critical study of the type specimens and fresh collections of N. alternifolia, as well as the protologues of both species, it is concluded that N. ‌motuoensis exhibits indistinguishable morphological characteristics from N. alternifolia. Therefore, N. ‌motuoensis is reduced here as a synonym of N. alternifolia. During the examination of the original materials pertaining to the basionym of N. alternifolia, i.e., Listera ‌alternifolia, it was observed that the name is based on multiple specimens (syntypes). Thus, a lectotype (K000387548) is selected here from the syntypes of L. ‌alternifolia (basionym of N. alternifolia). A detailed taxonomic study, along with descriptions, phenology, habitat, distribution, and illustrative photo-plates of N. alternifolia, is presented here for easy identification. The relationship between the two taxa has also been discussed, along with notes on the typification.

Taxonomic studies were done based on the specimens housed at various Indian herbaria (ARUN, ASSAM, BSHC, and CAL) and virtual foreign herbaria (AMES, BM, BR, E, K, L, M, P, PE, W, and Z). The live specimens were collected from the North District (now Mangan District) of Sikkim, India, during the field survey in July 2019. Photographs of the specimen were taken using Canon EOS 1300D DSLR Camera. The dissected floral parts were examined under Olympus Stereozoom Microscope SZ2-ILST. The herbarium was prepared as per the standard protocol (Jain & Rao 1977) and deposited at the Central National Herbarium (CAL), Botanical Survey of India, ‌Howrah. Available relevant literatures were consulted for solving taxonomic issues.

The type information of Listera ‌alternifolia was mentioned in the protologue as “SIKKIM: Lachen Valley, elevation about 10,000 feet, in flower in July; Pantling No. 390”. During the present study, we could locate several specimens with label data “Lachen Valley, elevation about 10,000 feet, in flower in July; Pantling 390” in different herbaria worldwide (AMES, BM, BR, CAL, K, L, M, P, Z).

The specimens associated with the label-data “Pantling 390” were collected at different times, i.e., “July 1895” and “July 1897”. It is worth mentioning that it was a practice of Robert Pantling to use the same number occasionally for the same taxon gathered at different times (Bhattacharjee & Bandyopadhyay 2022). The species was published in 1896, leading to believe that the collections dated “July 1895” constitute the type materials. King & Pantling (1896), while describing the species, had studied multiple specimens collected from Sikkim. As none of these were designated as ‘type’ or ‘holotype’, all these specimens are the syntypes according to Article 9.6 of ICN (Turland et al. 2025.

It is to be noted that the specimens collected in “July 1897” from “9000 feet elevation” are not the types. But, in some major herbaria (BR, E, K, L, Z), these specimens (BR0000020451820, E00394243, K000387549, L0061588, Z000078032) are erroneously annotated as types.

A total of 14 specimens (AMES: 1, BR: 1, CAL: 5, K: 2, L: 1, M: 1, P: 2, Z: 1) with the collection date “July 1895” and “elevation 10,000 feet” were found. Furthermore, CAL possesses more than one type specimen of L. ‌alternifolia (five specimens in total). Consequently, the term ‘holo’ used by Pearce & Cribb (2002) should be corrected to ‘lecto’ or ‘lecto­type’. But Pearce & Cribb (2002) did not use the phrase ‘designated here’ (hic designatus) or an equivalent, which is mandatory on or after 1st January 2001 for valid lecto­typification (fide Art. 7.11 of Madrid Code) and Art. 9.10 of ICN (Turland et al. 2025) cannot be applied to correct the typification (first-step lectotypification) done by Pearce & Cribb (2002) as their work has been published in 2002 (after 1st January 2001). However, a W-specimen cited by Pearce & Cribb (2002) could not be traced during the present study. Of the 14 extant type-specimens, one from K (K000387548) is complete in every respect, exhibiting intact flowers and roots and clearly demonstrating the phyllotaxy. The K specimen (K000387548) represents the most comprehensive original material of Neottia ‌alternifolia, exhibiting all the characteristics delineated in the protologue of the species (Fig. 2A). Hence, the specimen K000387548 is designated here as the lectotype of Neottia ‌alternifolia according to the Articles 9.3, 9.12 of ICN (Turland et al. 2025).

A herbarium sheet from K contains two sets (upper and lower) of plant specimens and two label-data with different collection dates “July 1895” and “July 1897”, with two barcode numbers K000387550 and K000387549, respectively. The K-specimen (upper set; three individuals) with barcode K000387550, collected in “July 1895”, directly pasted on the herbarium sheet with year “July 1895”, is the duplicate of the designated lectotype (K000387548). In contrast, another set of specimen (six individual) with barcode K000387549 with year “July 1897”, is a cutout from a different sheet and pasted later, is not the original material of the name as it is post-dated collection. The specimen with barcode K000387550 (isolectotype) is distinguished here from K000387549 (non-type material) by a red outline, as depicted in Figure 2B.

Neottia ‌motuoensis is a recently described species by Wen et al. (2024) based on the specimens collected from Xizang, Motuo County, Gedang Town, China (c. 3600 m) by Xiaohua Jin et al. (28 July 2023). Wen et al. (2024) noted that it was morphologically close to the Chinese species N. ‌yunnanensis. However, while describing the species, the authors (Wen et al. 2024) overlooked N. ‌alternifolia, which was also reported from China. Detailed study of the type specimens and fresh collections of N. ‌alternifolia (collected by SC & SS), and further comparative study of protologue and original illustrations of both the species proved that both are conspecific.

In the protologue of N. ‌motuoensis, it is mentioned that the species has a pubescent peduncle and two auricles at the base of the labellum, which is similar to N. ‌yunnanensis. But N. ‌motuoensis differs from N. ‌yunnanensis in having relatively short leaves (c. 1 cm long in N. ‌motuoensis, whereas more than 8 cm long in N. ‌yunnanensis), short rachis (2 cm long in N. ‌motuoensis, whereas c. 15 cm long in N. ‌yunnanensis), the number of flowers (c. 7-flowered in N. ‌motuoensis, whereas c. 35-flowered in N. ‌yunnanensis), lobules of the labellum short and rounded (long, ovate, acute in N. ‌yunnanensis). Additionally, N. ‌motuoensis has two leaves, which are “almost opposite”. However, the habit photographs of N. ‌motuoensis provided by Wen et al. (2024: f.1-right & f.2A) clearly demonstrated that the leaves are alternate or subopposite.

After a detailed study of the protologue (King & Pantling 1896) of Listera ‌alternifolia (basionym of Neottia ‌alternifolia), and relevant literatures (King & Pantling 1898; Pearce & Cribb 2002; Bhaumik & Pathak 2004; Lucksom 2007; Jin et al. 2014; Swami 2016), it is found that N. ‌alternifolia has 2 alternate or subopposite, more or less obovate or elliptic leaves, 0.6-1.6 cm long; puberulous pedunculate racemes bearing 7-9 distant nodding olive-green flowers arranged in a short rachis; labellum with a pair of auricles at base and rounded lobules at apex. Moreover, the protologues of both taxa confirm the presence of wart-like calli at the base of the labellum. The freshly collected specimens from Sikkim [S. Chakraborty & S. Sarkar 40142 (CAL0000266954, CAL0000266955)] also exhibit these characters. However, the photograph of N. ‌motuoensis, provided by Wen et al. (2024: f.2A), shows branching roots, which are probably resulted by contamination from another species (Fig. 3).

Neottia ‌alternifolia is distributed in the states of Arunachal Pradesh and Sikkim of India, and in Gongshan County, Yunnan of China. The type locality of N. ‌motuoensis is Gedang, Motuo (Mêdog) County, Xizang (Tibet), China, which is very close to Arunachal Pradesh, India, and an extended portion of the Eastern Himalayas. Consequently, not only the morphological characteristics but also the geographic distribution of these two species overlaps.

In light of the aforementioned discussion, Neottia ‌motuoensis should not be regarded as a distinct species. As N. ‌alternifolia has the priority as per Article 11 of ICN (Turland et al. 2025, N. ‌motuoensis is treated as an heterotypic synonym of N. ‌alternifolia in the present treatment.

The authors are grateful to the Director, Botanical Survey of India, ‌Kolkata, and the Head of Office, Botanical Survey of India, Sikkim Himalayan Regional Centre, Gangtok, and Central National Herbarium, Botanical Survey of India, ‌Howrah, for providing facilities and encouragement. The Ministry of Environment, Forests and Climate Change, New Delhi, is thankfully acknowledged for financial assistance under the Himalayan Research Fellowship Scheme of National Mission on Himalayan Studies (Project Ref. No. GBPNI/NMHS-2017 18/HSF-08). Authors are also thankful to Dr Norbert Holstein, Senior Curator in-Charge, Pteridophytes and General Herbarium I & II, Natural History Museum (BM), London, United Kingdom, for providing the images of specimens (BM000095769 & BM000095770). Authors are also thankful to the Forest Department authorities of Sikkim for providing the necessary permission and help during field surveys. They are thankful to the Subject Editor and reviewers for refining the manuscript.