Dendrocalamus atroviridis D.Z.Li & H.Q.Yang, 2016

Yang, Han-Qi, Xie, Ning, Sun, Mao-Sheng, Xu, Tian & Li, De-Zhu, 2016, Dendrocalamus atroviridis (Poaceae: Bambusoideae, Bambuseae), a new species from Southwest China, Phytotaxa 243 (2), pp. 170-174 : 171-173

Dendrocalamus atroviridis D.Z.Li & H.Q.Yang , sp. nov. (Figs. 1,2).

It is morphologically similar to D. brandisii but it differs by its dark green culms, grey culm sheaths with erect blade, smaller pseudospikelets and longer anthers and styles.

Type:— CHINA. Yunnan: Menghai County, Menghai Town , 1146 m a.s.l., edge of evergreen broad-leaved forest, 21 April 2015, H. Q. Yang, M. S. Sun & T. Xu 2015033 (holotype SWFC!; isotype KUN!) .

Arborescent bamboo; rhizomes sympodial; culms 10 − 15 m long, 5 − 10 cm in diameter; tip slightly pendulous. Internodes terete, with a ring of dense white tomentum below and above sheath scars; 45 − 65(− 85) cm long, wall 1 − 2 cm thick; dark green; sparsely white pubescent all over when young; usually covered with grey or white spots on the surfaces of 2 years old or older internodes; conspicuous aerial roots developed around the first to 15th nodes, up to ca. 6 − 7 m above ground. Branch complement developing from a solitary bud and usually beginning from the first node ca. 0.2 − 0.5 m above ground; branches several with 1 dominant; the branches at the lower half of the culm usually slender and reflexed. Culm leaves 35 − 45 × 30 − 42 cm, deciduous, thickly leathery, grey, covered with densely brown bristles and easily deciduous; auricles 1 − 2 mm long; oral setae absent; ligule 2 mm high, serrulate; blades erect, ovatetriangular to lanceolate, 5 − 20 cm long. Leaf sheaths pubescent when young; ligule 2 mm high; auricles absent; blades 5 − 10 per branch, narrowly lanceolate, 20 − 36 cm long, 2.5 − 4.0 cm wide. Flowering branches leafless, 0.8 − 1.5 m long; with 5 − 15 (− 20) pseudospikelets clustered in a spiky globose mass at each node of the flowering branches, each mass 0.6 − 1.0(− 1.5) cm in diameter; internodes 2.5 − 12.0 cm long, flattened along one side above the pseudospikelet cluster, covered with white setae. Bracts 2 − 3, 7 − 9 mm long, 8 − 10 mm wide. Pseudospikelets ovate-lanceolate, apically blunt, nearly glabrous, brown, 5 − 6 mm long, 2 − 3 mm wide. Florets 2 − 4. Glumes 1, 4 − 6 mm long, 3 − 5 mm wide, one-keeled; lemma broadly ovate, 0.4 − 0.6cm long, 0.5 − 0.6 cm wide, apex mucronate, 0.5 − 1.0 mm long; palea 0.4 − 0.5 cm long, 0.4 − 0.5 cm wide, 2 − keeled. Lodicules absent. Stamens 6; anthers yellow, ca. 5 mm long, and apex mucronate, purple, 0.5 mm long; filaments 0.6 − 0.8 cm long, free, white. Pistil 0.5 − 0.7 cm long, with short hairs. Ovary ovoid, hairy; stigma 1, plumose. Caryopsis nut-like, globular, 2 mm in diameter; pericarp yellow, thickly leathery, with a persistent style, ca. 1 mm long.

Etymology:—The epithet refers to the color of culms of this new species, especially the color of 2-year-old and older culms.

Taxonomic notes:— Dendrocalamus atroviridis morphologically resembles D. brandisii in general appearance, with white tomentum on the surface of the internodes when young and similar branching habit. However, D. atroviridis differs in having smaller culms, longer internodes, dark green culms, grey culm sheaths with erect blade, smaller pseudospikelets, and longer anthers and styles. These differences are summarized in the Table 1.

Distribution and habitat:— Dendrocalamus atroviridis is currently known from Menghai County, Xishuangbanna Autonomous Prefecture, Yunnan, China. Its habitat is evergreen broad-leaved forest at an altitude of ca. 1000–1300 m, with a typical tropical monsoon climate. Except Menghai County, this woody bamboo species is seldom introduced to cultivate elsewhere. On the other hand, D. brandisii is distributed in central, southern and southwestern Yunnan with a subtropical climate, but is rarely found in Xishuangbanna Autonomous Prefecture ( Fig. 3 ). This species is widely grown in the lower part of the mountains with thick soil layer, and banks of streams and rivers at altitude of ca. 1200–1800 m. Meanwhile, due to delicious bamboo shoots, D. brandisii is introduced to cultivate in South China.

Phenology:—We observed that this new species produces culm shoots in June–August, which are bitter. Flowering was noted in February–April, and fruiting in March–May.

Conservation Status: — Dendrocalamus atroviridis is only known from Menghai Town, Menghai County, Xishuangbanna Autonomous Prefecture, Yunnan, China. Dai people cultivate this bamboo for weaving, pulp and construction purposes. We only found one population comprised of 18 clumps of D. atroviridis at Menghai Town, including one flowering clump on 15 April, 2015, and two dead clumps which had flowered in 2014 or earlier.Although this species is easy to increase individual quantity because of its strong asexual reproduction capacity (e.g., dividing rhizome, culm cutting), further investigation and research into the range of this species would be needed to more fully assess of the conservation status.

Figures

FIGURE 3. Distributions of Dendrocalamus atroviridis (dot) and D. brandisii (shaded) in Yunnan, China. Map by Han-Qi Yang.