Bambusa rigida

Specimen: BS-0518 [C4] [N2] [S4] (living plants), received from cultivated stock as "Bambusa rigida" from Hawaii, USA, Aug. 2010; it was said that the plant was originally obtained from Yunnan, China.

Characteristics: Habit tight caespitose. Rhizome pachymorph, short-necked. Culms straight, erect, vertical or somewhat inclined, slightly bending above, to about 9 m tall. Young shoots [not yet observed in detail], emerge from late March to September. Culm-internodes terete, (37) 50–60 (65) cm long, mid-green, covered thinly with white long-lasting farina, thus appearing bluish, initially scantily scattered with short rigid white hairs, becoming scaberulous with age; diameter to 4 cm; thick-walled. Culm-nodes glabrous, flat; sheath scar marginally protruding 1 mm; supranodal line obscure, without a ridge, 5–7 mm above the nodal line; with a white farinose ring below the sheath scar when young; aerial roots none. Branch-buds solitary, subrotund with a pointed apex, the first 5–8 nodes without a bud. Branches several, slender, the central one usually slightly dominant, thin and subequal on the upper culm, the lower culm usually unbranched; branching intra­vaginal; rebranching. Culm-leaves deciduous. Culm-leaf sheaths 24 cm wide at the base, 23 cm long (on culms of 4 cm in diameter), shorter than the internode, usually 1/3 as long as the internode or a little shorter on the lower and mid-culm, about 1/2 as long as the internode on the basal culm, coriaceous, rigid, light green to light or mid-brownish when young, light straw-colored when dry, scattered with caducous short light-brownish soft hairs, densely towards the base, glabrous towards the apex, not farinose; margins eciliate; apex rounded, asymmetrical. Culm-leaf auricles unequal, not slanted, not wrinkled, mid-brown to dark brown and glossy when young, connection with the blade ca. 2–3 mm wide, the larger auricle narrowly oblong, about 22 × 4 mm, the smaller one oblong, about 10 × 4 mm; both with undulate bristles, ca. 5(?) mm long, white when young; auricles of the culm-leaves in thin culms or on the upper culm usually lobe-like protruding (6 × 1.5 mm) and not or loosely connected with the margin of the sheath apex, but narrowly (0.5–1 mm) and persistently connected with the blade base edge. Culm-leaf ligule 1–1.5 mm high, denticulate or ciliolate. Culm-leaf blades thickly papery, usually persistent, occasionally caducous, erect, mid-brown, early dried and fading to a light straw color, abaxially glabrous, broad triangular with rounded basal edges on the lower and mid-culm, lanceolate on the upper culm, nearly as long as a sheath on the mid-culm, 8 cm wide near the base, 21 cm long; margins distally convolute; apex long attenuate. Foliage-leaves 5–7 (13) per branchlet. Foliage-leaf sheaths green when young, straw-colored when dry, glabrous; margins eciliate. Foliage-leaf auricles protruding lobes, 2–3 mm long, with about 10 spreading pale 8–10 mm long bristles. Foliage-leaf ligule inconspicuous, less than 0.5 mm high, entire; outer ligule a rounded rim, margin entire. Foliage-leaf blades small, 12–19 × 1.5–2 (2.3) cm, lanceolate to linear-lanceolate, glabrous and almost glossy mid-green to dark green above, puberulous and dull green beneath; base unequally rounded to cuneate; apex attenuate; margins antrorsely scabrous; midrib proximally slightly prominent, light green; pseudopetiole 1–3 mm long. Flowers and seeds are unknown.

Uses: Culms for light construction; plants as garden ornamentals, for hedges and screening.

Cultivation requirements: Grows in part shade to full sun, sandy loam to clay loam, normal moisture-retentive to moist soil with good drainage. Tolerates wind.

Photos in Quindembo; BambooWeb.info [#1340].

Comments: A main key character of Bambusa rigida, "culm sheath blade nearly 1/2 width of sheath apex or narrower" (Flora of China, accessed 1 Jan. 2018 [#1303]) does not match with BS-0518, in which the blade base in mature plants is 3/4 as wide as the sheath apex. All checked vegetative characteristics of BS-0518 are more consistent with Bambusa textilis than B. rigida.