Chimonocalamus elegans Sungkaew & Teerawat., 2017

Teerawatananon, Atchara, Marod, Dokrak, Hodkinson, Trevor R. & Sungkaew, Sarawood, 2017, Chimonocalamus elegans, a new temperate woody bamboo species (Poaceae: Bambusoideae) from Doi Phu Kha National Park, Thailand, Phytotaxa 302 (1), pp. 97-100 : 99

Chimonocalamus elegans Sungkaew & Teerawat. , sp. nov. ( Fig. 1 )

Diagnosis: The new species differs from other members of Chimonocalamus in having glabrous nodes, culm leaf sheaths with narrow apex (3−4 mm) and 4−7 mm long ligules.

Type:— THAILAND. Nan Province: Doi Phu Kha National Park , 18°53’33.4”N, 101°12’59.7”E, ca. 1,700 m a.s.l., 24 August 2004, P. Pinyo s.n. (holotype BKF! , isotypes BK! , Natural History Museum, Thailand!).

Description:—Arborescent, unarmed bamboo. Rhizomes pachymorph with short necks, forming a dense clump of culms. Culms erect, 2−3 m tall, 0.8−1.2 cm in diameter, glabrous; nodes prominent, glabrous, the basal nodes with a ring of rootthorns that are 2−4 mm long; internodes terete, 10−20 cm long, walls thin, 1−1.5(−2) mm thick (mid-culm portion). Branches developing from the lower quarter or from around the mid-culm upwards. Mid-culm branch complement with 3 sub-equal branches at each node. Culm leaf sheaths 10−17 × 2−3 cm, top shallowly convex to truncate, back covered with sparsely appressed golden-brown hairs, especially at the upper half, margins scarious, apex 3−4 mm wide; culm leaf blades erect to patent, narrowly triangular, 4−6 × 0.15−0.3 cm; auricles absent, oral setae few, 1−1.5 cm long; ligule 4−7 mm long, margin fimbriate. Leaves 3−7 per branchlet; blade with inconspicuous transverse veins, 6−13 × 0.4−0.7 cm, glabrous, occasionally sparsely hairy on nerves, base rounded to acute or attenuate, apex acuminate, pseudo-petiole 0.2−0.5 cm long; leaf sheaths 1.5−3 cm long, glabrous, margins scarious; oral setae 3−7, 3−7 mm long; ligules membraneous, 0.5−1 mm long, margin irregularly toothed. Inflorescence semelauctant, a panicle (with a raceme-like arrangement of stalked spikelets), terminal to a leafy branch, 3−6 cm long; rachis filiform, 3−8 mm long. Spikelets 1.5−3 cm long; empty glumes 2, perfect florets 2−3 and vestigial terminal florets 1–2, disarticulating below each floret; glumes similar, coriaceous, 4−7 mm long, mucronate to acute, margins ciliate at upper half, 3−7-nerved; rachilla internodes between the florets compressed, 1−5 mm long, upper half pubescent; lemmas coriaceous, lanceolate, 7−9 mm long, mucronate to acute, margins ciliate at upper half, 7−9-nerved; paleas chartaceous, 3−8.5 mm long, 2-keeled, keels ciliate, 3-nerved between keels, 1-nerved on each wing; lodicules 3, membraneous, 0.8−1.5 mm long, margins ciliate; anthers 3, ca. 5 mm long, filaments free.

Ecology and distribution —It is only found at Doi Phu Kha National Park, Nan Province, Thailand. It grows in the understory of montane forest around the summit, at ca. 1,600 −1,700 m a.s.l.

Conservation status —According to the IUCN Red List criteria ( IUCN 2011), Chimonocalamus elegans could be considered as Endangered (EN) or possibly Extinct (EX). The taxon is known only from a single collection made in the Nan Province of northern Thailand in 2004 by Mr. Piya Pinyo, despite subsequent attempts by the authors to re-collect it. However, insufficient data exist regarding its distribution, so we provisionally assign the species conservation status as Data Deficient (DD).

Figures

FIGURE 1. Chimonocalamus elegans.A. Flowering branchlet; B. Portion of culm showing node; C. Culm leaves on the new shoot (flying shoot); D. Culm leaf sheaths; E. Spikelet without glumes; F. Glumes; G. Lemmas; H. Paleas; I. Lodicules. Drawn by A. Teerawatananon from P. Pinyo s.n. (BKF).