Dendrocalamus cauhaiensis N.H.Xia & V.T.Nguyen, 2013

1. Dendrocalamus cauhaiensis N.H.Xia & V.T.Nguyen View in CoL , sp. nov. — Fig. 1 View Fig , 2 View Fig ; Map 1 View Map 1

Species nova D. yunnanico Hsueh & D.Z.Li affinis, sed paleis 8–12 mm longis,et lemmatibus fertilibus 12–15 mm longis,culmorum vaginis dorsaliter apressis ateris pilosis,auriculis subfalcatis,setis oralibus hirsutis,setis 2.5–3 mm longis, ligulis 11 mm longis, fimbriatis, fimbriis irregularibus et glabris differt. — Typus: Van Tho Nguyen NVT 20091215 (holo FSIV; iso FSIV-CH, IBSC), Vietnam, Yen bai, Tran Yen, Luong Thinh, cultivated near stream, N21°39.931', E104°48.535', alt. 48 m asl, 15 Dec. 2009.

Etymology. The specific epithet refers to the place where this species has been planted for conservation, Cau Hai bamboo garden, located in a district where this species is indigenous. The garden is the oldest bamboo garden in Vietnam.

Arborescent bamboo, rhizomes pachymorph, short-necked. Culms erect, 18–20 m tall and 10–17 cm diam, apex erect or slightly nodding; internodes terete, up to 42–57 cm long, wall 1.5–2 cm thick, initially covered with white powder and glabrous, green when old, sheath scars not prominent and glabrous, intranode velutinous with a 9 mm high ring of rustycoloured hairs, infranode glabrous; dormant bud small, triangular, 9–12 by 8–11 mm; aerial roots developed at supranodal ridges. Branches several at each node, central dominant, no branches below 9–10 node, c. 4–4.2 m above ground. Culm sheaths caducous, distinctly leathery, abaxial with densely appressed black hairs, margins glabrous; apex broadly rounded; auricles subfalcate, 5– 6 by 1–2 mm, exserted from the sheath margin, bearing several 2.5–3 mm long setae; ligule 9–11 mm high, margin irregularly fimbriate, glabrous; blade reflexed, narrowly lanceolate, c. 1/5 as long as sheath proper, apex acuminate, adaxially white-tawny hispid, abaxially glabrous. Leaves (5–)7–9 per ultimate branch, sheath yellowish hispid; auricles absent; ligules truncate, c. 3 mm high, entire; pedicel 9–11 by 3 mm; leaf blade oblong-lanceolate, 28–33(–50) by 4.5–6.7(–12) cm, apex acute, base widely cuneate or nearly rounded, adaxially glabrous, abaxially rough, secondary veins 13–18 on each side of midrib. Inflorescence iterauctant, flowering branch with leaves, pendulous, with 1– 3 clustered pseudospikelets at each node; pseudospikelet ovate-lanceolate, 1.5–1.7 by 0.6–0.7 cm, apex acute; prophyll triangular, 1-keeled, 4 mm long, abaxially pubescent, adaxially thinly tomentose; florets 6 –7, all florets fertile, open when mature; rachilla-internodes short and not disarticulating. Glumes 1–2, 4–6 by 4–6 mm, abaxially puberulent in the middle, adaxially pubescent, margins long-ciliate, apex acute or blunt; lemmas broadly ovate, 12–15 by 8 –12 mm, both sides puberulent, margins ciliate, apex mucronate or acute; palea oblong-lanceolate, 8–12 by 2–2.5 mm, densely bristly on both sides, margins and keels pilose, 2-keeled, 2– 3-veined between and 2-veined on either side of keels, apex mucronate, apex of uppermost palea usually acute; lodicules 0–1, usually on uppermost floret. Anthers yellowish, 5–5.5 mm long, exserted, apex acuminate with few hairs; filaments distinct, separate; stamens 6. Ovary ovoid, hairy; stigma 1, hairless; pistil 15–17 mm long. Flowering observed in December, fruit unknown.

Distribution & Habitat — Dendrocalamus cauhaiensis is now commonly found in the remnants of degraded natural forest and cultivated in household gardens, near stream or hill base, between 50 and 100 m asl, in Tan Son, Cam Khe district, Phu Tho province, and Tran Yen district, Yen Bai provinces.

Phenology — Shooting season is from July to September.

Uses — Young shoots are sweet and used for food at the local and the culms are used for house construction as well as providing the raw material for making mat, chopstick.

Vernacular name — Mai cây.

Additional specimens examined. VIETNAM, Phu Tho, Doan Hung, Chan Mong,cultivated in Cau Hai bamboo garden, Van Tho Nguyen NVT 162 ( FSIV, FSIV-CH, IBSC), N21°31.895', E105°11.872', alt. 50 m asl, 5 Sept. 2010 GoogleMaps ; Tan Son, Thu Cuc , Van Tho Nguyen NVT 211 ( FSIV, IBSC), N21°14.709', E104°56.928', alt. 143 m asl, 17 Sept. 2010 GoogleMaps ; Cam Khe, Phuong Vy , Van Tho Nguyen NVT 217 ( FSIV, FSIV-CH, IBSC), N21°26.263', E105°01.466', alt. 106 m asl, 17 Sept. 2010 GoogleMaps .

Note — Dendrocalamus cauhaiensis bears a close resemblance to D. yunnanicus in general appearance, but it is distinct in its culm sheath auricles subfalcate, culm sheath ligules 11 mm high, irregularly fimbriate, culm sheath proper covered with appressed black hairs, palea 8 –12 mm long, and fertile lemma 12–15 mm long. The distinguishing characters are presented in Table 1.

mm