Gigantochloa marga

Specimen: BS-0077 [N4] (living plants) = Widjaja G-4761, received from the USA in 2012.

Characteristics: Habit unicaespitose, dense. Rhizome pachymorph, short. Culms straight, erect, slightly bending outwards above, tips drooping, 17 m long [ultimate height not yet known]. Young shoots conical; sheaths green with yellowish stripes and black hairs; culm-leaf blades erect, green; emerge from May to August. Culm-internodes terete, 23–41 (51) cm long, green, with narrow yellowish stripes on the lower culm when young, glabrous, smooth, with irregular small or large dark brown splotches when mature, scattered with a few appressed short black hairs below the nodes; diameter 4–7 cm [ultimate diameter not yet known]; walls thick. Culm-nodes flat; nodal line horizontal; sheath scar not or minutely protruding; supranodal line more or less obscure, without a ridge, 10–13 mm above the nodal line; aerial roots present on basal nodes only. Branch-buds solitary, ovate, subrotund, or triangular with all edges round, present from the basal node up. Branches several, unequal, to about 1 m long, 0.2–0.7 cm in diameter, the central one somewhat dominant and 1.3 (2.5) m long, 0.7–1 cm in diameter, unbranched on the basal and lower culm; branching intravaginal; rebranching except the shorter branches. Culm-leaves early deciduous on branched nodes, late deciduous on unbranched nodes, persistent on the basal culm. Culm-leaf sheaths triangular with a truncate top, 34 cm wide at the base, 26 cm long, as long as the internode on the lower culm, somewhat shorter on the mid-culm and upper culm; leathery, brittle, green with yellowish stripes when young, with a temporary pale and gray tiger-stripe pattern when becoming dry, fading to a plain light straw-color and with longitudinal patches of appressed black hairs when old; apex truncate, with the middle part convex-raised, symmetrical, with tiny, 1 mm high triangular sheath extensions on both apex edges; sheath margins short pale ciliate when young, eciliate and entire when dry. Culm-leaf auricles small, equal in shape and size, ovate, 14 mm wide, 4 mm high, erect, adnate to the basal margins of the blade and extending towards but not reaching the sheath margins, glabrous, entire, dark brown and glossy when young, fading to dull brown with age. Culm-leaf ligule 2–3 mm high, entire. Culm-leaf blades thickly papery, persistent, erect, triangular on the basal, lower, and mid-culm, shape gradually changing to lanceolate on the mid and upper culm, about 8 cm wide at the base and 17 cm long on the lower culm; adaxially scattered with loosely appressed black hairs, abaxially glabrous, adaxially green with yellowish stripes when young, light straw-colored when dry; apex short-attenuate; margins scabrous. Foliage-leaves (5) 6–9 (11) per branchlet. Foliage-leaf sheaths keeled on the back; green when young, straw-colored when dry; with some patches of rough short appressed black hairs, otherwise glabrous; apex truncate; margins short ciliate. Foliage-leaf auricles small, rounded, erect, glabrous, reddish, ca. 1 mm high, 1.5 mm wide; margins entire. Foliage-leaf ligule 1–2 mm high, reddish; margin entire; outer ligule a low glabrous ridge. Foliage-leaf blades rigid, lanceolate, (27) 35–45 (50) × (3.5) 4–5 (7) cm; glabrous on both surfaces, medium green to dark green; base rounded to wedge-shaped; apex short attenuate; margins antrorsely scabrous; midvein proximally prominent, yellowish green beneath; pseudopetiole 3–6 (10) mm long. Flowers and seeds are unknown.

Uses: Plants as garden ornamentals, for hedges and landscaping.

Comments: The culm-leaves of "Gigantochloa marga" show some similarities with Gigantochloa nigrociliata. Both species have sheath extensions on both apex edges, but they are tiny, only 1 mm high and lower than the adjacent auricles, and triangular in "Gigantochloa marga", whereas taller than the adjacent auricles and horn-shaped in Gigantochloa nigrociliata. Further, the culm-leaf ligule in "Gigantochloa marga" is entire but denticulate in Gigantochloa nigrociliata. At least in BS-0553, identified as Gigantochloa nigrociliata, the base of the triangular culm-leaf blade is narrower than the blade base in "Gigantochloa marga".