Indosasa sp. (?)

Distribution: THAILAND (North), wild, possibly introduced and naturalized.

Specimen: BS-0010 (living plant) [BBG], Phrae Province, northern Thailand, without precise locality, wild, received from ธ. ล., 21 July 2011.

Characteristics: Habit grove-forming, erect. Rhizome leptomorph. Culms stiffly erect, [ultimate height not yet known]. Young shoots light green to medium green; emerge from February to July. Culm-internodes medium green, rough when young, initially scattered with soft erect pale hairs, becoming glabrous soon, terete, (not?) flattened above the bud-bearing side [not yet observed], [length and diameter not yet measured]; walls thick; [lacuna not yet observed]. Culm-nodes glabrous, smooth, prominent; nodal line a somewhat prominent, corky, horizontal and narrow ring, when young with a short sharply contoured densely-white farinose ring below, fading early; sheath scar not protruding; supranodal line clearly discernible, with a prominent ridge, green to purplish when young, in diameter one and a half times the diameter of the internode, about 1 cm above the nodal line; aerial roots none. Branch-buds solitary, triangular, from the basal node up. Branches single (or 1–3?) on the mid-culm, almost as thick as the main culm, initially strictly upright (parallel to the main axis), 3 branches on the upper culms; lower culm unbranched; branching typically intravaginal, occasionally extravaginal on the lower culm; rebranching (?) [not yet observed]. Culm-leaves deciduous. Culm-leaf sheaths green when young, light straw-colored when dry, about 1/3 of the internode length, glabrous, initially thinly farinose; apex horizontally truncate; margins green to purplish when young, pale ciliolate. Culm-leaf auricles tiny, projecting, with a few spreading long pale bristles. Culm-leaf ligule short, convex, margin entire or ciliolate. Culm-leaf blade linear-lanceolate, green with a purplish tint when young, strongly reflexed. Foliage-leaves 7–12 per branchlet. Foliage-leaf sheaths green, glabrous (?), apex green to purplish when young. Foliage-leaf auricles inconspicuous, dull purplish when young; with several to many long pale spreading bristles. Foliage-leaf ligule inconspicuous. Foliage-leaf blades lanceolate, mid-sized, glabrous on both surfaces, medium green; base rounded to cuneate; apex attenuate; margins antrorsely scabrous; midvein not or slightly prominent; cross veins clearly visible; pseudo-petiole short, glabrous. Flowers and seeds are unknown.

Provisional identification: A species of Indosasa or, less likely, Chimonobambusa.

Comments:

(1) The plant grows well in the Chiang Mai climate.

(2) Species of Indosasa occur naturally in southern China, Vietnam, and Laos, but have not yet been recorded from locations in Thailand. It is likely that this species was introduced and has become casually present, or has become naturalized in a small region.