Bambusa sp. (TH: Kanchanaburi 1)

Specimen: BS-0918 [N3] (living plant); อ. ทองผาภูมิ (Thong Pha Phum District), Kanchanaburi, western Thailand, wild, coll. by บ. ต., received as "ไผ่ตาย้าย (phai ta yai), ไผ่ย้ายกอ (phai yai ko)", 9 Jan. 2017.

Characteristics: Habit open caespitose. Rhizome to about 40 cm long, pachymorph, distally usually thicker than the culm. Culms straight, erect, slightly bending above, ultimate height over 12 m. Young shoots conical, sheaths initially greenish, changing to pale orange soon, farinose and scattered with dark hairs; culm-leaf blades initially erect on the top, spreading on elongated shoots, the lower ones somewhat deflexed, greenish, glabrous, with conspicuous pale bristly dark colored auricles; emerge from March to November. Culm-internodes terete, 50–60 (69) cm long, glabrous, green, and farinose (thus appearing bluish green) when young, dull green when old; basal diameter to about 7.5 cm; thick-walled, wall 1.0–1.3 cm by 4.5–5.0 cm in diameter at 1.1 m above the ground. Culm-nodes glabrous, smooth, flat (slightly prominent in thin culms); sheath scar not or marginally protruding; supranodal line discernible, with or without a slight ridge, about 1 cm above the nodal line; with a white farinose ring below the sheath scar when young; occasionally with short aerial roots on the basal culm. Branch-buds solitary, rotund, from the basal node up. Branches initially 3, central one dominant, to ca. 2 m long, two side branches subdominant, with a few to several additional smaller branches on the upper culm; usually unbranched on the lower culm, but a single thick branch may occasionally develop; branching intravaginal; rebranching. Culm-leaves deciduous, the very basal ones may occasionally remain persistent and decay on the culm. Culm-leaf sheaths an isosceles trapezoid, 10–12 cm long, one-fifth to one-sixth as long as the internode, thickly papery, glabrous, light brownish green, evenly covered with a white mealy-waxy, easily removable deposit when young, thus appearing bluish, light straw-colored when dry; margins eciliate; apex horizontal-truncate, symmetrical or slightly asymmetrical. Culm-leaf auricles conspicuous long lobes, adnate to and contiguous with the basal margin of the blade, extending to the sheath margin and protruding the margin almost 1 cm, each auricle 3–4 cm long, 0.5–1 cm high, waved, horizontally deflexed, margin throughout with 0.5–2 cm long light brownish horizontally oriented and waved bristles. Culm-leaf ligule 2–4 mm high (to 5 mm in the middle), entire, eciliate, blackish when young. Culm-leaf blades coriaceous, caducous, deflexed to horizontally deflexed, green and glabrous on both surfaces, light straw-colored when dry, broadly lanceolate, 4–6 cm long, 2–3 cm wide on the lower culm, about half as long as a sheath on the lower and mid-culm, and as long as a sheath on the upper culm; junction with sheath about to 3 cm wide; apex attenuate. Foliage-leaves (8) 9–10 (11) per branchlet. Foliage-leaf sheaths keeled, mid-green, glabrous, smooth, margins eciliate. Foliage-leaf auricles none, bristles none. Foliage-leaf ligule 2–3 mm high, green, entire; outer ligule small, callus-like. Foliage-leaf blades tough, medium-sized, (15) 24–33 (42) × (2) 3–5 (7) cm, lanceolate to oblong-lanceolate, glabrous on both surfaces, mid to dark green above, bluish-green beneath; base unequally rounded to wedge-shaped; apex attenuate; margins antrorsely scabrous; midrib proximally prominent on both surfaces, yellowish green beneath; pseudopetiole 2–4 mm long. Flowers and seeds are unknown.

Uses: Young shoots for food, palatable; culms for construction; plants for landscaping.

Cultivation requirements: Easy and fast-growing; in part shade to full sun, sandy loam to clay loam, normal moisture-retentive to moist with good drainage.

Images: Photos by Buntoon Tohtong on Facebook, 12 July 2016.

Provisional identification: Bambusa sp.

Comments:

(1) The auricles resemble Bambusa farinacea, B. longispiculata, and Dendrocalamus sikkimensis.

(2) Foliage-leaf auricles: In young culms, only the terminal leafy part of the main axis may develop auricles with bristles (long-bristly lobes). Whether they are persistent or caducous could not be observed. All other leafy branches on the succeeding axes don't develop auricles at all. It may be in branchlets of young plants that auricles and bristles are present only in the lower ca. 2–3 leaves, but usually not developed on the succeeding upper leaves.

(3) The description of vegetative characteristics of Bambusa griffithiana match quite well with BS-0918. However, the description is not detailed enough, and moreover, B. griffithiana is considered to be a scrambling bamboo with leaning culms, whereas BS-0918 has upright culms.