Schizostachyum sp. (TH: Ranong, Chumphon)

Thai name: No known records.

Distribution: THAILAND (South): Provinces of Ranong and Chumphon.

Culm size: Ultimate height and diameter unknown.

Characteristics: Habit caespitose. Rhizome pachymorph. Culms straight, over 5 m long [ultimate height not yet known], erect below, bending above, arching down to the ground. Young shoots light green, farinose and dark hairy, emerge from July. Culm-internodes terete, 35-41 cm long, light green and slightly farinose when young, glabrous, smooth and yellowish-brown with age; diameter 1–1.5 cm [ultimate diameter not yet known]; walls 3 mm and lacuna 5 mm at the lower culm of 11 mm diameter, walls 1.5 mm and lacuna 7 mm at the mid-culm of 10 mm diameter; easily splittable; lacuna without pith. Culm-nodes glabrous, flat; sheath scar soft pale hairy when young, somewhat corky; nodal ridge clearly discernible, glabrous; with a white farinose ring below the sheath scar when young; without aerial roots. Branch-buds solitary, from the basal node up. Branches several, unbranched on the basal and lower culm (on about 5 nodes from the base up), 3–5 branches on the lower and upper culm, 5–9 on the mid-culm, thin, subequal, almost of the same diameter, short, 60–80 cm long; branching intravaginal. Culm-leaves early deciduous. Culm-leaf sheaths 12–17 cm long, papery, green, scattered with short dark brown caducous hairs and slightly farinose when young, light straw-colored and almost glabrous when dry; margins eciliate; apex deeply concave-truncate. Culm-leaf auricles inconspicuous, wide but very low rims, with whitish straight but usually veered 8–12 mm long early caducous bristles. Culm-leaf ligule short, entire. Culm-leaf blades papery, early caducous, horizontally patent to reflexed, linear-lanceolate, somewhat twisted, 3–6 cm long, about 0.4 cm wide near the base, 0.2 cm at the junction with the sheath. Foliage-leaves 6–10 per branchlet. Foliage-leaf sheaths green, with a few pale erect, early caducous soft hairs, glabrous with age; margins eciliate. Foliage-leaf auricles none, bristles none. Foliage-leaf ligule short, entire. Foliage-leaf blades (20) 24–32 × (2.0) 2.5–4.5 cm, lanceolate, glabrous on both surfaces, green, slightly glaucous beneath; base rounded to wedge-shaped; apex attenuate, often bent or twisted; margins antrorsely scabrous; midrib proximally slightly prominent on both surfaces; pseudopetiole (3) 7–10 mm long, glabrous. Flowers and seeds are unknown.

Comments: This bamboo, BS-0089, was originally assumed to represent Schizostachyum fimbriatum, syn. Neohouzeaua fimbriata. When the plant had gained sufficient size after planting, its characteristics could be checked in more detail in July 2017. It turned out that this bamboo was not Neohouzeaua fimbriata. The main differences are: BS-0089 has no membraneous layer in the lacuna of the internodes, has much shorter culm-leaf blades, has none or inconspicuous auricles in the culm-leaves and foliage-leaves, and has smaller foliage-leaf blades. BS-0089 is possibly another, maybe still undescribed species of this genus, Schizostachyum.