Schizostachyum cambodianum Merkl., Chhang & K. M. Wong

(3) Schizostachyum cambodianum Merkl., Chhang & K.M.Wong (in Merklinger et al. 2017: 84, figs. 1, 2). Figs. 1K–M. Type: — CAMBODIA, Veal Viang District, Phnom Samkos Wildlife Sanctuary, Yai Mau Shrine area, alt. ca. 875 m, 12° 12’ 38.6” N, 102° 53’ 55.2” E, 25 November 2015, Merklinger FFM 2015-76 (holotype: SING [SING0285986, SING0285987, SING0285988!]; isotypes: K & Forestry Administration Cambodia). Distribution and ecology: —The known distribution range of S. cambodianum, so far, covers the southwestern part of Cambodia in Pursat and Ko Kong Provinces and southeastern Thailand in Trat Province where its small population exists in an evergreen forest. Additional specimens examined:— THAILAND: South-eastern. Trat, Ko Kut, 9 November 2005, A. Teerawatananon & S. Sungkaew 691 (Thailand Natural History Museum); the same locality, 3 April 2006, A. Teerawatananon & S. Sungkaew 918 (Thailand Natural History Museum); the same locality, 10 November 2022, S. Sungkaew & A. Teerawatananon 1760 (Thailand Natural History Museum); the same locality, 10 November 2022, S. Sungkaew & A. Teerawatananon 1762 (Thailand Natural History Museum); the same locality, 10 November 2022, S. Sungkaew & A. Teerawatananon 1763 (Thailand Natural History Museum). CAMBODIA: Koh Kong Province, 18 August 2016, F.F. Merklinger 2016-17 (SING0282012, SING0282013); Pursat Province, Phnom Sam Los Wildlife Sanctuary, March 2015, F.F. Merklinger 2015-47 (BKF210512, SING0245535). Conservation status:— Schizostachyum cambodianum has a very small EOO of less than 100 km 2 (28.8 km 2) which places it in the Critically Endangered (CR) conservation category while a small AOO of less than 500 km 2 (28.0 km 2) places this species in the Endangered (EN) category. This bamboo species occurs on a small island “Ko Kut (Kut Island)” in Trat Province, Thailand. This can be regarded as a single severely fragmented population. According to IUCN (2023), we consider the conservation status of S. cambodianum Critically Endangered [CR B1, B2a]. Vernacular name:— ไผ่กะแสนย้อย (Phai Kasaen Yoi). Notes: — Schizostachyum cambodianum was first described from the Cardamom Mountains in Cambodia. This is a new record for Thailand. Schizostachyum cambodianum found on Ko Kut (Kut Island) shows some morphological differences from the populations found in the Cardamom Mountains (Merklinger et al. 2017) such as having a faintlykeeled palea and more hairs on the culm and leaf sheath.