Bambusa nghiana V.T. Tran, 2021

Tran, Van Tien, 2021, Bambusa nghiana sp. nov. (Poaceae: Bambusoideae), a new species from Thanh Hoa Province, Vietnam, Adansonia (3) 43 (19), pp. 217-221 : 218-221

Bambusa nghiana V.T. Tran , sp.nov.

( Figs 1 ; 2 )

This species is distinguished from the closely related Bambusa gurgandii K.M.Wong & Diep by having long internode, blade with non spreading lobe-like auricles, auricles upcurved at the end, 2-4 perfect flowers.

TYPUS. — Vietnam. Thanh Hoa Province, Quan Son District, Son Dien Commune, Ban Village , elevation 700 m, 20°27’0.227”N, 104°81’0.713”E, 3.IX.2019, H.N. Nguyen HNN0067 (holo-, Dalat University [ DLU]!); iso-, VNMN!, Tay Nguyen Institute for Scientific research [VTN] !).

DISTRIBUTION AND HABITAT. — This species is growing along roads or forest edges in Son Dien Commune, Quan Son District, Thanh Hoa Province, Vietnam. Shoot season is from August to October.

ETYMOLOGY. — The new species is named in honor of Dr Nguyen Hoang Nghia, for his contributions to the bamboo research in Vietnam.

VERNACULAR NAME. — Lùng.

LOCAL USES. — This species is economically valuable to the local people. Its shoots can be used for food, while the culms are often used for house construction, split form as material for making handicrafts, tightening rice cake (the local populations harvest from the wild).

DESCRIPTION

Woody bamboo, rhizomes pachymorph, short-necked. Culm erect, plain color, green when young maturing to yellow, 13-15 m tall, 7-10 cm in diameter. Culm internode terete, basal internode covered with appressed pale hairs with a consistent narrow ring of dense appressed hairs at each node, with a slight white-waxy bloom just above, 60- 80 cm long, or up to c. 100 cm long; wall thin, often less than 9 mm thick. Branches usually absent on lower culm, branches at mid-culm with the primary axis dominant in size with 2 or several higher-order subequal branches from its base. Culm sheaths on mature culm 25-35 cm long, pale green, infused with white green or yellow green at the top and dense black hairs at the base; basal part at the sheath insertion with a 2-3 mm long, narrow ring-like band of dense dark brown hairs 2-3 mm long; blade 5-8 cm long, broad triangular, erect, not tightly appressed against the next sheath or internode green, with a slight white-waxy bloom on abaxial side, with 1-2 cm long pale brown bristles at the base of the margins; auricles 7-10 mm high, protruding, 1-2 cm long and slightly upcurved at the end, purplish brown with sinuous bristles on the edge 5-10 mm long, ligule a leathery low subentire rim 2-2.5 cm high with narrow triangular margin teeth. Leaves 18-20 × 2.9-3 cm, green on the adaxial side and white green on the abaxial side, glabrous on both surface; auricles with a conspicuous laterally spreading narrow lobe 0.5-1 mm high and 1-2 mm long, upcurved at the end, margins with spreading bristles 1-2 cm long; ligule inconspicuous; sheath glabrous. Inflorescences iterauctant, with the basis flower-bearing unit consisting of pseudospikelets comprising prophyllate buds at their base with the spikelets proper distal to these, the prophyllate buds themselves developing into new pseudospikelet. Pseudospikelet, when mature, pink, 2-2.5 × 1-1.5 cm, each with 1-3 bracts subtending prophyllate buds, large one 0.3-0.5 cm long; 1 empty glume with ciliae margins, 2-4 perfect flowers and 1 terminal vestigial flower consisting of palea only, c. 1 cm long; rachilla internode 0.3-0.5 cm long, glabrous and disarticulating between flowers. Flower with lemma 1-1.5 × 0.5-0.8 mm, 18-20 veined, back glabrous and pink, apex acuminate c. 1 mm; palea 1-1.1 × 0.5-0.8 mm, 2-keeled, back strongly sulcate, 14-16 veined, glabrous, apex acuminate, the keel thickened, glabrous, the wing 4-veined, glabrous but minutely ciliate margins; lodicules 3, oblong or triangular, 2-3 mm long, 1-2 mm wide, bearing 1-2 mm long cilia on the margins; stamens 6 pink, filaments free, anther 2-3 mm long when extruded; ovary c. 1 mm long, ovoid, with thick long hairs c. 1 mm long, style c. 1 mm long bearing 3 linear stigmas c. 2.5 mm long with short hairs. Fruit a caryopsis, obovoid, 5-7 mm long, apex conspicuous acute tip c. 1 mm, hairy.

REMARKS

Bambusa nghiana sp. nov. is placed in subgenus Lingnania by the characters of culm internodes long, branches usually absent on lower culm, flowers purple. Otherwise, this species may be close to Bambusa gurgandii , a species discovered in Khe Tre area, Nam Dong District, Thua Thien Hue Province. It is similar to B. gurgandii in basal part at the sheath insertion with a narrow ring-like band of dense spreading hairs, large auricles protruding. However, the new species differs from the latter by having long internode, blade with non spreading lobe-like auricles, auricles upcurved at the end, 2-4 perfect flowers, one terminal vestigial flower. Differences are summarised in Table 1 .

Figures

FIG. 1. — Bambusa nghiana V.T. Tran, sp. nov.: A, pseudospikelet; B, two bracts subtending prophyllate buds; C, rachilla segment; D, flower; E, lemma, dorsal view; F, palea, dorsal view; G, palea, ventral view; H, terminal vestigial flower; I, anther; J, ovary; K, fruit; L, M, lodicules. Drawing by V.T. Tran from the type specimens. Scale bars: A, 1 cm; B, 0.5 cm; C, F, G, 0.2 cm; D, E, 0.3 cm; H, J, 1 mm; I, L, M, 1.5 mm; K, 2.5 mm. Drawn by V.T. Tran.

FIG. 2. — Bambusa nghiana V.T. Tran, sp. nov.: A, clump; B, culm and branches complements; C, young shoot; D, section of shoot; E, ventral view of culm sheath; F, lateral view of culm sheath; G, leaf-complement; H, section of upper leaf-complement; I, section of below leaf-complement; J, part of flowering branch. Photos by H.N. Nguyen.