Dendrocalamus dienbienensis H. N. Nguyen & V. T. Nguyen 2017, sp. nov.
Creators: name: Nguyen, Hoang Nghia
name: Nguyen, Van Tho
name: Nguyen, Anh Dung
name: Vien, Nguyen
name: Tien, Pham Quang
name: Tran, Van Tien
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Poaceae
Dendrocalamus
Dendrocalamus dienbienensis

description: Dendrocalamus dienbienensis H.N.Nguyen & V.T.Nguyen, sp. nov. (figs. 1, 2)
Diagnosis: —It is similar to D. nianhei in having pseudospikelets with florets opening when mature, big-sized culm, big leaves and basal nodes without branches, but differs culm internodes covering densely white-brown velvets, lemma glabrous on both sides, palea with 3 veins on wings, and a 7 mm high ring of velvets below sheath scar (see table 1)
TYPE: — VIETNAM. Phu Tho province: Doan Hung district, Chan Mong Commune, 21032 ’8.34’’, 105011 ’ 47,75’’, elev. 50 m, 13 February 2017, V.T. Nguyen NVT424 (holotype: VNMN!, isotypes: Herbarium of Vietnamese Academy of Forest Sciences (VAFS)!, Forest Science Centre for Central Northern Vietnam of VAFS (FSCC)!).
Arborescent bamboo, rhizomes pachymorph, short necked. Culms erect, 23–25 m tall, 16–22 cm diameter, apex nodding; internodes 19–30 cm long, wall 2.5–3.0 cm thick, initially densely white-brown velutinous, with a 8 mm high ring of yellowish velvets above sheath scar, with a 7 mm high ring of brown velvets below sheath scar; basal nodes with a ring of aerial roots. Branches many, subequal at mid-culm, dominant branch unclear; branching from 18 th –20 th node up, about 5–6 m above ground. Culm sheaths deciduous, proper leathery, 37–46.6 × 53–72.5cm, abaxially densely appressed black setose; margins sericeous; apex nearly round; auricles absent; ligule 7–10 mm high, serrulate; blade erect, short, garlic-shaped, black, 1/3 as long as sheath proper, adaxially dense yellowish velutinous, abaxially glabrous, margin ciliate. Leaves (5–)8–11(–15) per ultimate branch, sheaths white hispid, sheath apex thinly pubrulent; auricles absent; ligule truncate, 2–3 mm long, margin entire, thinly pubrulent; leaf blade oblong-lanceolate, (26–) 32–36 × 5–8 cm, very thin, pedicel 4–6 × ca. 2.5mm, base nearly rounded, both sides glabrous, apex acute, veins 12–14 pairs. Inflorescence bracteate, iterauctant; flowering branches leafless, pendulous, with (2–)3–4 clustered pseudospiklets at each node; pseudospikelets ovate-lanceolate, 12–15 × 4–6 mm, brown; florets 5, all florets fertile and each floret opening when mature; rachilla-internodes short and not disarticulating;prophyll triangular, 3.4–4.2×2.7– 3.0 mm, 1-keeled, margins and keel dense long-ciliate, apex blunt. Glumes 2, 6–8 mm long, both sides glabrous, margins long ciliate, apex acute; lemmas broadly ovate, (11–)12–13 × (7–) 9–10 mm, both sides glabrous, manyveined, margin long-ciliate, apex acute or obtuse; palea narrowly lanceolate, 10.5–13 × 4–5 mm, 2-keeled, pilose on keels, 4(–5)-veined between keels and 3-veinded on each wing, both glabrous, apex bifid, rarely acute, margin long-ciliate; lodicules absent. Stamens 6, anthers yellow, 6.5–7.1 mm long, anthers exserted when mature, apex acute, with several white hairs; filament free. Ovary narrowly lanceolate, hairy, base with stalk ca. 0.4–0.6 mm, glabrous; stigma 1, hairless, purple; pistil (10–) 11–15 mm long. Flowering in August, fruits unknown.
Etymology: —The specific epithet refers to Dien Bien province where discovered this species.
Distribution and habitat:—This species is cultivated in Muong Phang, Na Tau, Na Nhan Communes, Dien Bien District, Dien Bien province, Vietnam and introduced to Chan Mong commune, Doan Hung district, Phu Tho province, Vietnam. The flowers as well as other material were collected from cultivated clumps in Chan Mong commune, Doan Hung district, Phu Tho province, Vietnam in 2017 and these plants originate from Muong Phang commune. The other vegetative materials were also gathered in Chan Mong and Muong Phang commune (see distribution in fig. 3). Shoot season is from May to September.
Local Uses:—This species is economically valuable to the local people. Its shoot can used for food, and the culms are often used for house construction, water tube and general household use, and can be used a raw material for paper-pulp production.
Vernacular name: —BƯƠng lông điện biên, BƯƠng lớn, Mạy púa.
Relationships: — Dendrocalamus dienbienensis has many characters of subgeneric Sinocalamus Hsueh & Li (1996:153), such as pseudospikelets with many florets, basal nodes of culm without branches, and big leaves. This species may be more or less close to large-stature species of subgeneric Sinocalamus by each floret opening when mature and culm with hairs, particular to D. nianhei Nguyen & Le (2012: 426) discovered in the close area. D. dienbienensis has many characters of D. nianhei, such as culm with a about 8 mm high ring of velvets above sheath scars, subequal branches at midculm, basal nodes of culm without branches, auricles of culm sheath small, blade of culm sheath erect and garlic-shaped, auricules of leaf absent and big leaves. However, the new plant has many differences, such as culm internodes covering densely white-brown velvets, lemma glabrous on both sides, palea with 3 veins on wings, and a 7 mm high ring of velvets below sheath scar. D.sinicus Chia & Sun (1982: 10) is another species of genus Dendrocalamus that may be related D.dienbienensis and be distinguished from the new plant by its bigger pseudospikelets (30–35 mm in length), anther longer (8–12 mm in length), steril floret at the apex, and sparsely dentate ligule of leaves.
Additional specimens examined (paratypes): — VIETNAM. Dien Bien: Dien Bien District, Muong Phang Commune, 210 27.942’N, 103008.879 ’E, alt. 1028 m, 19 August 2010, V. T. Nguyen NVT099 (Paratype: FSCC!, IBSC!); Phu Tho: Doan Hung District, Chan Mong Commune, 21031,721 ’N, 105011,804 ’E, alt. 69 m, 2 August 2010, V. T. Nguyen NVT014 (Paratype: FSCC!, IBSC!).
description: Published as part of Nguyen, Hoang Nghia, Nguyen, Van Tho, Nguyen, Anh Dung, Vien, Nguyen, Tien, Pham Quang & Tran, Van Tien, 2017, Dendrocalamus dienbienensis (Poaceae: Bambusoideae), a new species from Northern Vietnam, pp. 290-296 in Phytotaxa 327 (3) on pages 291-295, DOI: 10.11646/phytotaxa.327.3.9, http://zenodo.org/record/13722520