Arundinella kokutensis (Poaceae, Arundinelleae), a new species from south-eastern Thailand
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- Teerawatananon, A., Sungkaew, S. & Hodkinson, T.R. Kew Bull (2009) 64: 747. doi:10.1007/s12225-009-9168-5
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Arundinella kokutensis Teerawat. & Sungkaew is described and illustrated here as a new species from Kut Island, Trat Province, Thailand.
The genus Arundinella was established by Raddi (1823) based on the type species Arundinella brasiliensis Raddi collected from Brazil but now recognised as A. hispida (Willd.) Kuntze. This genus is distinguished by its paired, 2-flowered spikelets which disarticulate above the glumes, scabrid upper lemmas, punctiform hilums and short membranous ligules. Clayton & Renvoize (1986) reported that there are about 50 species of Arundinella, distributed chiefly in Asia, an estimate that has now been raised to approximately 60 species (Sun & Phillips 2006).
Among the specimens of the genus Arundinella collected from Thailand, a very distinctive collection, Charoenphol et al. 5104 from Kut Island, Trat Province, Southeastern Thailand was previously labelled as Arundinella metzii Hochst. ex Miq. After re-collecting and critically examining both living and herbarium specimens, from the same locality, their morphology could not be matched with the species descriptions or type specimens of A. metzii (Hohenacker 297 (K)), nor any other Arundinella species. Neither do they fit within the natural range of morphological variation found within those other species. Therefore, a new species A. kokutensis Teerawat. & Sungkaew is described here.
Arundinella kokutensisTeerawat. & Sungkaewsp. nov. Species A. metziae Hochst. ex Miq. et A. holcoidi (Kunth) Trin. affinis, sed ab illis ramis et pedicellis fere glabris, glumis imus glabris, aristis lemmatium superiorium 5 – 6.5 mm longis, staminibus 2 differt. Typus: Charoenphol et al. 5104 (holotypus K!; isotypi BKF!, C!, E!, NY!).
Distribution. Endemic to Thailand.
Specimens Examined. Thailand. Trat: Ko Kut, (12°35'N 101°31'E), 21 Nov. 1970, Charoenphol et al. 5104 (BKF, C, E, K, NY); loc. cit., 3 April 2006, Teerawatananon & Sungkaew 914 (BKF, TCD, Herbarium of Thailand Natural History Museum, National Science Museum & 3 April 2006, Teerawatananon & Sungkaew 917 (TCD, Herbarium of Thailand Natural History Museum, National Science Museum).
Habitat. Growing on shaded, moist and mossy granite rocks, along streams in tropical monsoon rainforest.
Etymology. This species is named after the island (‘Ko’ in Thai) called Kut, Trat Province, southeastern Thailand, where this plant was collected for the first time.
Conservation Status.Arundinella kokutensis is extremely restricted in distribution and specific habitat, occurring in small populations. It is very likely an endemic to Ko Kut. We recommend treating this species as Vulnerable (VU) D1 D2 until more data are obtained.
Morphological variation in Arundinella kokutensis and its close relatives, A. holcoides and A. metzii.
glabrous or pubescent
(3 −) 10 – 25 cm long, an open panicle, sometimes drooping
3 – 15 (− 20) cm long, a narrow panicle
up to 50 cm, an open panicle
almost glabrous, rarely scabrous
scabrous and pilose with tubercle-based hairs
glabrous, sometimes sparsely pilose
1 – 1.5 mm long
1 – 1.3 mm long
c. 1 mm long
0.3 – 0.5 mm long
0.2 – 0.3 mm long
0.4 – 0.5 mm long
5 – 6.5 mm long
4 – 4.5 mm long
c. 3 mm long
2 (extremely rarely 3)
The authors are grateful to the curators and the staff of the following herbaria: BKF, C, E, K, and NY for the use or loan of specimens. Thanks to Prof. Dr Pranom Chantaranothai for his kind comments and useful suggestions, to Prof. John Parnell and Dr Pimwadee Pornpongrungrueng for their support of the work, and Prof. Dr Benjamin Øllgaard for help with the Latin diagnosis. This work was supported by the TRF/BIOTEC Special Program for Biodiversity Research and Training Grant T_148026.