Gigantochloa sp. (TH: Kanchanaburi)

Specimen: BS-0600 [BBG] (living plant), cult., from Mr. Sombat (Sombut Bamboo), Suan Phai Pho Phiang สวนไผ่พอเพียง, Kanchanaburi, received from ธ. ล. as ไผ่ป่า (phai pa), 1 Dec. 2010.

Characteristics: Habit caespitose, tight clump. Rhizome pachymorph. Culm stiffly erect, bending above from the weight of foliage; height not recorded, possibly over 15 m tall. Young shoots emerge from May to October. Culm-internode striped, the stripes narrow, initially in various shades of violet and green, turning into various shades of green, occasionally on the upper half sparsely black hairy; wall very thick on the lower culm, nearly solid, apically thin-walled, splinters easily. Culm-node slightly prominent; nodal line with sheath scar slightly protruding, vested with a narrow soft pale hairy ring when young; supranodal line discernible, without a ridge; with aerial roots on the basal nodes. Branch-bud solitary. Branches from the base up, directed horizontally, downward and upward on the lower culm, the central branch notably dominant, with 2 subdominant lateral branches and many thin, subequal branches, branching extravaginal and intravaginal; rebranching. Culm-leaves persistent. Culm-leaf sheath of 1/2 length of the internode or shorter, light green when young, light straw-colored when dry, with irregular patches of dense, appressed stiff black hairs; margins black ciliate; apex truncate, in larger sheaths somewhat concave-truncate. Culm-leaf auricles conspicuous, oval-shaped lobes, erect, protruding, dark brown when young, light straw-colored when dry; margin entire, without bristles. Culm-leaf ligule short. Culm-leaf blade triangular on the lower culm, lanceolate on the upper culm, erect, glabrous, light green with reddish tint when young, light straw-colored when dry. Foliage-leaves more than 10 per branchlet. Foliage-leaf sheath light green or yellowish-green when young, initially with some pale hirsute hairs, soon becoming glabrous. Foliage-leaf auricles large, parabolic, light green to orange, turning dark. Foliage-leaf ligule short, margin entire; outer ligule conspicuous. Foliage-leaf blade large, glabrous on both surfaces, bright green above, bluish-green beneath; midvein conspicuous, yellowish, prominent beneath; pseudopetiole 1 cm long.

Cultivation requirements: Easy and fast-growing; in full sun, the soils normal moisture-retentive to moist.

Comments: The identification of BS-0600 remains unresolved. It could be a species of the genus Gigantochloa or Bambusa. Since the plant has left Bambusetum Baan Sammi, it cannot be re-examined.