Dendrocalamus sp. (VN)

Specimens: BS-0776 [E1-R07] (living plant), raised from seeds, the seeds from FMXG, Yunnan, China, as "越南龙竹 (yuènán lóng zhú), Vietnam Dragon Bamboo, Dendrocalamus sp.",  collected in Vietnam, without precise locality, in Apr. 2013, received 14 Oct. 2013.

Characteristics: Habit tight caespitose. Rhizome pachymorph, short. Culms straight, ultimate height and diameter not yet known (4 m long, 1.6 cm in diameter, in June 2021). Young shoots conical, dark green, culm-leaf blades erect to deflexed; emerge from May/June. Culm-internodes terete, medium green, distally with short soft pale caducous hairs when young, soon becoming glabrous, 35–50 cm long. Culm-nodes glabrous, smooth, somewhat prominent; nodal line horizontal, sheath scar a low corky ring, marginally protruding; supranodal line clearly discernible, with a ridge, somewhat farinose and rough below the nodal line. Branch-buds solitary, broader than tall, from the basal node up. Branches several, unequal, the central one dominant; lower culm unbranched; branching intravaginal and extravaginal; rebranching. Culm-leaves deciduous. Culm-leaf sheaths soft, papery, green when young, covered with caducous appressed initially pale hairs, becoming dark brown to blackish; sheath orange-brown when dry, with somewhat darker patches, and with many small circular and oval-shaped dark brown spots, and a few bigger dark brown spots; apex narrow, horizontally truncate; margins short pale ciliate. Culm-leaf auricles conspicuous, somewhat outward-bent lobes, rounded at the ends and protruding from the sheath margin, purplish-black when young, margins with long pale spreading bristles. Culm-leaf ligule low, dark purplish when young, with irregular triangular teeth narrowing into long erect pale bristles. Culm-leaf blades soft, papery, persistent or caducous, initially patent, reflexed when old, narrowly lanceolate, base constricted, junction with the sheath much smaller than the sheath apex width. Foliage-leaves ca. 10 per branchlet. Foliage-leaf sheaths rounded, green when young, glabrous; margins eciliate. Foliage-leaf auricles small lobes, more or less sickle-shaped, protruding and bent outwards, dark purplish when young, glabrous; margins with numerous straight or waved spreading pale bristles. Foliage-leaf ligule inconspicuous; outer ligule a low ridge. Foliage-leaf blades large, 33–42 × 8.5–11.5 cm, broadly long-lanceolate, glabrous above, pubescent beneath; base rounded to wedge-shaped; apex acuminate; midrib distinct, proximally prominent; pseudopetiole short.

Seed viability: Unknown, viability is assumed to last at least several months.

Seed weight: 10 g ≈ 300–330 dried spikelets (husk-wrapped seeds).

Seed germination: (1) Seeds laid on moistened tissue paper, 15 Oct. 2013, 23–30 °C day temperature, diffuse light, 18–22 °C night temperature, atmospheric humidity >70%, the primary roots developed after 6 days, the first coleoptiles emerged after 10 days, germination rate 30% by 5 Nov. 2013. — (2) Germination rate 40% with temperatures 22–26 °C, using a sterile soilless potting mix as substrate (composted pine bark, peat moss, worm casts, perlite, and clay, 6 pH) (F. C., 26 Nov. 2013).