Gigantochloa sp. (TH: Krabi) 2

Specimen: BS-0562 [E2] (living plant), Krabi, southern Thailand, near the coast, wild, coll. C. S., #3064, received 2 June 2010.

Characteristics:

(1) Habit tight caespitose; clump to about 9 m tall, with 13 m long culms, or a little longer, arching in a narrow bow down to the ground. Rhizome pachymorph. Culms erect and unbranched below. Young shoots emerge late, from June to September. Culm-internodes 22–30 (33) cm long, mid-green, with light green and cream narrow stripes of various widths, distally with scattered short rigid pale or dark hairs, rough when old; diameter to 3.5 (3.8)  cm; thick-walled. Culm-nodes not prominent. Branches several, the central one dominant, with 2 subdominant side branches, and few to several smaller branches; branching intravaginal. Culm-leaves persistent on the lower culm, deciduous on the upper, branched culm. Culm-leaf sheath leathery, parabolic, 9–13 cm wide at the base, 11–17 cm long, about half the length of the internode or a little shorter, light green when young, straw-colored when dry, with mid-brown hairs becoming dark; margins eciliate(?), entire when old; apex horizontally truncate or slightly convex, 1.5–3 cm broad. Culm-leaf auricles rim-like, about 1 mm high or lower, entire; bristles none. Culm-leaf ligule low, ca. 1–2 mm high, with about 5 mm long erect pale persistent bristles. Culm-leaf blade reflexed, early or late caducous, narrow long-triangular, about half as long as the sheath, hairy adaxially at the connection with the sheath when young. Foliage-leaves (5) 7–9 (13) per branchlet. Foliage-leaf sheath initially hispid, light green with the apex reddish when young, yellowish and glabrous when old; margins eciliate(?). Foliage-leaf auricles conspicuous, entire, rarely with a few whitish bristles. Foliage-leaf ligule short, entire. Foliage-leaf blades papery, (7) 10–18 (28) × (1.0) 1.3–1.7 (3.0) cm, mid-green, glabrous on both surfaces; margins antrorsely scabrous; base cuneate; apex acuminate to attenuate; midrib proximally prominent; pseudopetiole 1–3 mm long, light green, glabrous. Flowers and seeds are unknown.

(2) Culm size dimensions: Basal culm 0.15 m above the ground, culm diameter 2.50 cm, very thick-walled (almost solid), wall thickness 1.10 cm, lacuna diameter 0.30 cm; lower culm 0.9 m, diameter 2.20 cm, very thick-walled, wall 0.90 cm, lacuna 0.40 cm; mid-culm 4.1 m, diameter 1.40 cm, thick-walled, wall 0.35 cm, lacuna 0.70 cm; upper culm 6.6 m, diameter 0.50 cm, thick-walled, wall 0.20 cm, lacuna 0.10 cm; culm apex 9.4 m.

Uses: Plants have potential as garden ornamentals and for landscaping.

Cultivation requirements: Easy-growing; in full sun, on heavy soil, moist soil preferred, though quite drought-resistant.

Provisional identification: Although flowers are not known, the vegetative parts suggest a species of Gigantochloa. This bamboo was originally assumed to represent Gigantochloa scortechinii. However, young culm sheaths are not orange in color, and internodes are not farinose as they are in Gigantochloa scortechinii.

Comments:

(1) The species could prove to be salt tolerant, as it grows in former mangrove habitats.

(2) There are some similarities with the as-yet unidentified Gigantochloa species BS-0567 from Phang Nga.