Schizostachyum mekongensis (A.Camus) K.M.Wong & Sungkaew

Sungkaew, Sarawood, Wong, Khoon Meng, Hodkinson, Trevor R., Thammanu, Siriluck, Cheysawat, Somboon & Teerawatananon, Atchara, 2024, Taxonomic revision of the bamboo genus Schizostachyum (Bambusoideae: Melocanninae) in Thailand, with two new species and five new records, lectotypifications and nomenclatural corrections, Phytotaxa 676 (3), pp. 263-286 : 278-279

(11) Schizostachyum mekongensis (A.Camus) K.M.Wong & Sungkaew (in Goh et al. 2020: 117).

≡ Neohouzeaua mekongensis A. Camus (1922: 101) .

Type: — THAILAND, Expédition du Me-kong , Ubon, 1866–1868, M.le Dr Thorel s.n. (lectotype: P [P03652490, digital image!] designated by Goh et al. (2020); isolectotypes: P [P03652489, digital images!] & US [ US 00132832, digital images!]; probable isolectotype: Ubon, Bords du Mekong, C. Thorel s.n., 1866–1868 K [K000290745!].

Supported by epitype: THAILAND, Ubon Ratchathani, Khong Chiam , 15 November 2017, Sungkaew 1570 (epitype designated by Sungkaew et al. (2021: 146): BKF!; isoepitypes: BK, KUFF!, SING!, Thailand Natural History Museum!) .

Description & distribution: —fide Sungkaew et al. (2021).

Additional specimens examined: — THAILAND: Eastern. Ubon Ratchathani, Kaeng Tana , 15 November 2017, S. Sungkaew 1571 (Thailand Natural History Museum) ; Khong Chiam , 15 November 2017, S. Sungkaew 1569 (Thailand Natural History Museum) ; Pho Sai , 17 November 2017, Sungkaew 1573 (Thailand Natural History Museum) .

Conservation status: — Schizostachyum mekongensis has a small EOO of less than 5,000 km 2 (837.0 km 2), that puts it in the Endangered (EN) conservation category and a small AOO of less than 500 km 2 (104.0 km 2) that also places it in the EN category. In addition, the populations were found in less than five locations and this may lead to a very high risk of extinction in the wild. According to IUCN (2023), S. mekongensis fits well with the conservation status of the Endangered [EN B1, B2a] category.

Vernacular name: —ไผ่โขง (Phai Kong), ไผ่แม่โขง (Phai Mae Khong).

Notes: —The protologue of S. mekongensis ( Camus 1922) described 3–4 empty glumes in a pseudospikelet. However, our morphological examination of the holotype of S. mekongensis (P03652490) shows that its pseudospikelets bear 1–2 bracts subtending prophyllate buds instead of empty glumes.