Schizostachyum sp. (Songkhla)

Schizostachyum sp.

    Culm-node, with branches almost as thick
    as the main culm, and with a prominent
    corky sheath scar ring (BS-0551)

  • Thai name: Not recorded.
  • Distribution: THAILAND (South): Songkhla.
  • Culm size: Ultimate height and diameter unknown.
  • Specimens: BS-0551 (living plants), อุทยานแห่งชาติ เขาน้ำค้าง Khao Nam Khang National Park, Songkhla, southern Thailand, coll. by C.S., #3053, as "seedling, Gigantochloa sp.", received 30 May 2010.
  • Characters: Habit tight caespitose. Rhizome pachymorph. Culms to 6 m long [ultimate size not yet known, supposed not exceeding 10 m], erect to slanted below, bending above, and arching almost to ground. Young shoots [not yet observed] emerge June(?) – October. Culm-internodes terete, 45–60 (65) cm long, light green, with short white fuzz when young, otherwise smooth, 0.8–1.5 (1.6) cm in diameter [maximum size not yet known], easily splitting; walls thin, about 1 mm on a branch with 7 mm in diameter; lumen with a layer of soft white pith. Culm-nodes initially covered with white caducous fuzz, then glabrous, smooth, not prominent; but with a prominent corky sheath scar ring, mid to dark brown when young, blackish when old, 2 mm high, and 2–4 mm protruding the node; with a slight nodal ridge 5–10 mm above nodal line; with a whitish to bluish fuzzy ring below nodes when young; bud solitary, broad; basal nodes without aerial roots, the 2–4 lowest nodes branchless and without buds. Branches 3–6, the central branch somewhat less thick than the main culm, the other branches less thick than the central branch but not very slender, all branches on lower and mid-culm stiffly rising up (negative phototropic) at an angle of 10–30°; branching extravaginal and infravaginal, perhaps also intravaginal [not yet observed]. Culm-leaves late deciduous, or loosely attached, or persistent and decaying on culm. Culm-leaf sheaths 9–12 cm long, about ¼ of internode length, leathery to thickly papery, rough, with very short white caducous hairs, light green and basally pinkish when young, light straw-colored when dry, somewhat dark spotted with age; margins narrowly dark colored when young, pale ciliolate or eciliate; apex horizontally truncate. Culm-leaf auricles small, inconspicuous, dark colored when young, with a few short white caducous bristles. Culm-leaf ligule short, 1 mm, entire [not yet observed in detail]. Culm-leaf blades papery, early deciduous, erect, long-triangular, basal edges rounded; base as broad as sheath apex; blade apex long-attenuate, reddish-brown when young, light straw-colored when dry. Foliage-leaves 6–10 (12) per branchlet. Foliage-leaf sheaths keeled, glabrous, light green when young, margins eciliate. Foliage-leaf auricles inconspicuous. Foliage-leaf ligule usually conspicuous, 2–6 mm long, light green to light orange when young, margin with very short white straight caducous bristles. Foliage-leaf blades large, 28–50 (60) × (2.5) 4–8 (11.5) cm, lanceolate, glabrous on both surfaces, light green; base unequal, rounded to wedge-shaped; apex attenuate; margins retrorsely scabrous; midrib on both surfaces proximally prominent, whitish green; petiole long, 8–12 mm.
  • Comments: (1) Flowers and seeds unknown. (2) It is still unclear into which genus this bamboo can be placed. It is herein provisionally assigned to Schizostachyum but there is more reason to exclude it from Schizostachyum than to retain this assignment. There are slight similarities with Schizostachyum grande with regard to the general appearance of the culm-leaf sheath and culm-leaf blade, and a strong similarity with regard to the pronounced nodes thickened by a corky girdle. However, this bamboo differs from all known species of Schizostachyum by its branching type which consists of a few thick subequal branches, at least on lower and mid culm. (3) Apparently, the leaves of this bamboo look chlorotic and do produce a low amount of chlorophyll, thus remain light green. The light green color seems to be stable. The plant is slow-growing. Soil deficiencies could not be ruled out.