Guadua aculeata

Thai name: ไผ่กวัดัวยักษ์ (phai kwadwa yak).

Distribution: THAILAND, introduced about 2010, in cultivation. — From MEXICO to CENTRAL AMERICA.

Culm size: Height 15–25 (30) m, diameter 15–18 (22) cm.

Description: "… caespitose; clumped loosely. Rhizomes elongated; pachymorph. Culms erect, or geniculately ascending, or arching; 1000–1500 cm long; 100–150 mm diam.; woody; with root thorns from the nodes. Culm-internodes terete; with small lumen; distally hispid. Lateral branches dendroid. Branch complement two, or three. Culm-sheaths deciduous; hispid; without auricles; glabrous on shoulders. Culm-sheath ligule ciliolate. Culm-sheath blade triangular; as wide as sheath at base; demarcated but persistent; erect. Leaf-sheaths keeled; striately veined; glabrous on surface; outer margin glabrous, or hairy. Leaf-sheath oral hairs lacking. Leaf-sheath auricles absent. Ligule an eciliate membrane. Collar with external ligule. Leaf-blade base cuneate; with a brief petiole-like connection to sheath; petiole 0.5 cm long; petiole glabrous. Leaf-blades lanceolate, or oblong; 15–19 cm long; 28–30 mm wide. Leaf-blade midrib conspicuous. Leaf-blade venation without cross veins. Leaf-blade surface pilose; sparsely hairy; hairy abaxially. Leaf-blade apex acuminate. … [flowers and seeds described]". — Kew GrassBase [#1335].

Images: Photos by Niramit Sareerudt on Facebook, 24 Jan. 2014 (flowers).