Nianhochloa bidoupensis, H. N. Nguyen & V. T. Tran, 2012

Nguyen, Hoang Nghia & Tran, Van Tien, 2012, Nianhochloa gen. nov. (Poaceae, Bambusoideae), a new bamboo genus endemic to Bidoup Mountain, southern Vietnam, Adansonia (3) 34 (2), pp. 257-264 : 259-260

Nianhochloa bidoupensis

H.N.Nguyen & V.T.Tran, sp. nov. ( Figs 1 ; 2 ) Rhizomata sympodiales, culmi scandentes, 0.3-0.4 cm in diam., internodiis 20-22 cm longis. Inflorescentiae terminales, spiculae 2 florae, pseudospiculae bractea brevior lemmate, internodii rhachillae 2-3 mm longae, flos cum 3 lodiculis, 6 staminibus filamentis liberis, atque 3 stigmatibus.

TYPUS. — Vietnam. Lam Dong Province, Bidoup Mountain, Hon Giao Peak , elevation 1650 m a.s.l., 108 ° 42’54.7”E, 12 ° 11’12.8”N , VI.2006, H. N. Nguyen , V. T. Tran 62006601 (holo-, FSIV! [ Herbarium of Forest Science Institute of Vietnam]) .

OTHER MATERIAL EXAMINED. — Vietnam. Annam , Nha Trang, 1800 m a.l.s., 26. V.1922, Poilane 3688 (P!).

DISTRIBUTION, HABITAT AND PROPOSED CONSERVATION STATUS. — The species Nianhochloa bidoupensis sp. nov. is endemic to Bidoup Mountain, in the southern highlands of Vietnam and is assessed as Critically Endangered because its EOO (extent of occupancy) is less than 100 km 2. Otherwise, it grows sparsely scattered on Hon Giao peak, Bidoup Mountain, and is not known from any other locality. Therefore, the species should be regarded as Critically Endangered (CR) according to the World Conservation Union (IUCN) threat categories ( IUCN 2001). Associated species at the type locality include: Fokienia hodginsii Henry & Thomas (Cupressaceae) , Podocarpus imbricatus Blume , Podocarpus neriifolius D.Don (Podocarpaceae) , Quercus macrocalyx Hick. & Cam. , Quercus langbianensis Hick. & Cam. (Fagaceae) and Camellia sp. ( Theaceae ).

PHENOLOGY. — Its flowering period extends from June to August (as seen during 2006-2010). New shoots are developed between June and August.

ETYMOLOGY. — The specific epithet refers to the type locality, Bidoup Mountain , Lac Duong District, Lam Dong Province, Vietnam .

DESCRIPTION

Rhizomes pachymorph. Culms scrambling, 3-8 m tall; internodes 20-22 cm long, 0.3-0.4 cm in diameter; walls 0.5-1 mm thick. Branch complement derived from single buds at a culm node developing into 3-4 of subequal branchlets, subequalling internode. Culm leaves early deciduous; sheaths attenuate toward the apex, when young covered with sparsely appressed purple hairs on the abaxial side, margins densely covered with white cilia; 6.5-8 × 1-1.5 cm; blade triangular, apex acute, erect,2-2.5 × 0.1-0.2 cm, white cilia at the base on the adaxial side; ligule rim low, white cilia c. 0.1 cm long. Leaf blades 8-10 per branch, oblong-obovate, slightly narrow or obtuse at the base, margins serrate, 14-16 × 2.5-2.8 cm, veins 5-6 pairs; leaf sheaths purple, margins bearing dense white hairs at the upper part; auricles rim low or inconspicuous with slender bristles 0.4-0.6 cm long; ligule rim low, c. 1 mm long, ciliate; pseudo- petiole c. 1mm long. Inflorescences iterauctant, of pseudospikelets, initiating at the end of a leafy branch; pseudospikelets typically 1-2 cm, consisting of 2-3 small empty bracts, 1-2 bracts subtending prophyllate buds, 1-3 empty glumes (shorter than the lowest lemma); two (rarely one or three) perfect flowers and a terminal vestigial flower; uppermost glume 5-6 × 2-3 mm, ciliate on the abaxial surface, apex acuminate, mucronate; rachilla internodes between flowers glabrous, 2-3 mm long; lemma glabrous, 7-9 × 3-4 mm, with a mucronate tip, c. 1 mm, veins 9-10; palea 2-keeled, equalling or subequalling lemma, glabrous, transparent, veins 9-10; lodicules 3, c. 2-3 mm, glabrous transparent, protruding at the base, 2-3 × 1-2 mm; stamens six, filament free, 4-5 × c. 0.5 mm; stigmas three, white plumose, arising directly from the ovary summit, hairy; ovary dense white hairs at the apex; caryopsis c. 5 × 2 mm, with a flattened surface.

Figures

FIG. 1. — Nianhochloa bidoupensis H.N.Nguyen & V.T.Tran, sp. nov.: A, culm leaf;B, leafy branch;C, section of leafy branch;D, young branches at node; E, branch complement at midculm; F, leafy flowering branch; G, 2-keeled prophyll from the base of inflorescence, ventral view;H, pseudospikelet;I, pseudospikelet with florets open;J, pseudospikelet with rachilla between florets;K, lemma;L, ventral view of palea; M, dorsal view of palea; N, ventral view of lodicule; O, dorsal view of lodicule; P, stamen; Q, pistil with three stigmas; R, fruit. Drawn from type H.N. Nguyen, V.T. Tran 62006601. Scale bars: A, 0.5 cm; B-G, Q, not to scale; H-J, 2.5 mm; K-M, 1.7 mm; N-O, 1.5 mm; P, 1.5 mm; R, 2.5 mm.

FIG. 2.— Nianhochloa bidoupensis H.N.Nguyen & V.T.Tran, sp. nov., slides by authors from type locality; A, high mountain habitat (alpine forest); B, clump, C, bottom of clump, D, rhizome with extended necks; E, young branches at mid-culm; F, branch complement at mid-culm; G, leafy branch; H, section of leafy branch showing lower leaf surfaces; I, section of leafy branch showing upper leaf surfaces.