Gigantochloa wrayi
Gigantochloa wrayi Gamble, Ann. Roy. Bot. Gard. (Calcutta) 7, 1896: 64.
Synonym: Gigantochloa maxima var. viridis Holttum, Gard. Bull. Singapore, 16, 1958: 115.
Thai name: ไผ่คายดำ (phai khai dam) (Krabi); BKF Forest Herbarium does not list a Thai name for this species.
Malay names: buloh beti; buloh mata rusa; muloh minyak.
English name: Wray's Bamboo.
Distribution: THAILAND (South): Provinces of Chumphon, Krabi, Nakhon Si Thammarat, and Trang; in lowland forest at 50–100 m altitude. — MALAYSIA (Peninsular): northern part, in lowlands, also cultivated in villages. — INDONESIA: Sumatra. — Perhaps also in MYANMAR.
Descriptions:
(1) "Culms medium sized, up to 7 cm. thick, not hairy; culm-sheaths up to 27 cm., dark-hairy when young, blade reflexed, green when young, narrow and narrowed to the base, dark-hairy on the upper surface; auricles firm, low, entire, with a few bristles near the outer ends; ligule lacerated with the lacerations prolonged into bristles, up to 1 cm. high; leaf-blades up to 40 x 6 cm., lower surface fine-hairy; stalk 8 mm. long; auricles small, often bristly; ligule short. …" — H. B. Gilliland & al., Revised Flora of Malaya, vol. 3, 1971: p. 33 [#1039].
(2) "Culm sheaths green, occasionally streaked with paler green, covered with dark brown hairs; blade broadly lanceolate, spreading to reflexed; auricles low rims 0.5–1.5 mm high, glabrous to frequently with scattered fine bristles near the ends; ligule 6–11 mm long, deeply divided to form bristle-like lacerations 3–7 mm long. Culms to 6–12(–15) m tall, commonly 2–8(–12) cm diameter; internodes 25–40 cm long, dark green, occasionally streaked with paler yellowish green at the basal part of the culm, without white wax, with scattered dark hairs near the top of the internode. Leaf: blades 9–40 cm long, 1.2–6 cm wide, pale short-hairy below; stalk 2.5–4 mm long; auricles small lobes hardly 0.5 mm high, glabrous to fine-bristly; ligule a subentire rim 0.5–1.5 mm long, not bristly … [flowers described]." — K. M. Wong, Bamboos of Peninsular Malaysia, 1995: p. 142-143, fig. 80 [#1210].
(3) "Densely tufted, sympodial bamboo. Culm erect, slightly arching outwards, up to 12 m tall, diameter 2–20 cm, plain green or sometimes streaked yellow at the base; internodes non-waxy, up to 40 cm long, with scattered appressed dark-brown hairs on the upper parts; nodes not conspicuously swollen. Branches at each midculm node arising from a single bud, consisting of a dominant primary branch, 1–2 subdominant branches from its base and several lesser branchlets of higher orders. Culm sheath pale green, sometimes with faint yellow stripes, covered with dark brown hairs; blade broadly triangular on lower sheaths, broadly lanceolate on midculm and upper sheaths, green or sometimes flushed purple, spreading to reflexed, hirsute at base and along midrib on lower half; ligule lacerate, the base 1–2 mm tall, the lacerations to 8 mm long, bristly along rim when young; auricles low and rimlike, 2–4 mm long, sometimes raised at the outer ends, glabrous except for a few scattered pale bristles 2–5 mm long near the outer ends, dark green to dark purple. Leaf blade 9–40 cm × 1.5–6 cm, lower surface covered with soft pale hairs; ligule subentire, not bristly, 1–2 mm long; auricles small rounded lobes 1–2 mm long. Pseudospikelet 10–20 mm long, with 2–3 gemmiferous bracts, 3–4 glumes, 3–4 perfect florets and a vestigial terminal floret represented by an empty lemma 8–17 mm long. Caryopsis cylindrical-ellipsoidal, about 10 mm long, grooved on one side, apex thickened and hairy." — K. M. Wong in S. Dransfield & E. A. Widjaja (eds.), Plant Resources of South-East Asia No. 7, Bamboos, 1995: p. 124-126, fig. [#1226].
(4) E. A. Widjaja, Revis. Malesian Gigantochloa, 1987: p. 339-341, fig. 18-19 [#1224].
(5) "Culms densely tufted, straight and erect, up to 12 m tall, 4—10 cm in diameter; internodes to 50 cm long, green, glaucous, scattered with dark-brown hair when young; nodes not swollen; walls relatively thin, about 0.6—0.8 cm thick at mid-culm portion. Branches developing only on the upper part of the culms; mid-culm branch complements with several branches at each node, the primary one dominant, 1—2 subdominant branches from its base and often several lesser branches. Culm leaves deciduous, coriaceous-crustaceous, yellow-green, 21—27 cm long by 16—25 cm wide, top slightly convex or truncate to slightly concave, back covered with appressed dark-brown hairs; blades lanceolate, reflexed, 14—16 cm long by 2.5—3 cm wide near the base, covered with dark brown hair on adaxial sides; auricles continuing from base of the culm-leaf blade, rim-like, almost reach edges of the sheath, about 1—2 mm tall by 15—20 mm long, margins fringed with bristles 5—10 mm long, readily deciduous; ligules irregularly dentate, up to 5 mm high, fringed with readily deciduous bristles to 5—10 mm high. Leaves 4—8 per branchlet; blades 7—25 cm long by 0.8—2.5 cm wide, lower surface pubescent, tessellate, bases oblique-acute to oblique-rounded, pseudo-petiole 3—8 mm long; leaf sheaths 5—9 cm long, covered with white to pale-brown hair when young then become glabrous; auricles small, ear-like or lobe-like, up to 1 mm long, glabrous, sometimes fringed with bristles 2—3 mm long at the end of the lobe; scale-like callus inconspicuous to present, glabrous, 1 mm by 2 mm, margin sub-entire or covered with minuscule spines; ligule low rim 1 mm high, margin irregularly dentate, sometimes fringed with bristles up to 2 mm long; secondary veins 7—9 pairs, intermediate veins 5—7. … [flowers described, seeds unknown]". — C. Rattamanee, Revis. Gigantochloa in Thailand, 2014: p. 124-129, fig. 48-50 [#1225].
(6) J. S. Gamble, Bambuseae Brit. India, 1896: p. 64 [#1230].
(7) Kew GrassBase [#1335].
Images: Line drawing in J. S. Gamble, Bambuseae Brit. India, 1896, pl. 55 [#1230].
Uses: Culms for construction such as building houses, bridges, fences, and scaffolding; for furniture making such as chairs, tables, and shelves; for tool making such as fishing rods, spears, knives, incense sticks, musical instruments, and household tools; split culms for handicrafts such as baskets, cages, mats, hats, and other woven handicrafts. Young shoots for food. Leaves for food packaging. Plants for erosion control and other environmental purposes. (Recorded uses acc. to ChatGPT 3.5, accessed 20 March 2024).
Flowering cycle: Unknown. "Flowering occurs on one to several culms in a clump, which can continue to show new vegetative growth during and after such flowering" [#1226].
Seed viability: Unknown, viability is assumed to last at least several months.
Comments: Closely related to Gigantochloa scortechinii, which has farinose internodes, whereas Gigantochloa wrayi is not farinose.
Gigantochloa wrayi — old generation
Thai names: Not recorded.
Distribution: MALAYSIA, in cultivation.
Gigantochloa wrayi (BS-0303): Young shoot with culm-leaf, showing a patent culm-leaf blade, and a tall brownish lacerated ligule which extends into whitish bristly fringes (left); internode on lower culm (center); habit of the plant, which is in an early stage of flowering, 1st March 2017 (right)
Specimen: BS-0303 [C9] (living plants), received from Rimba Ilmu Botanical Garden, Malaysia, as "Gigantochloa wrayi", by C. S. in Sep. 2009.
Characteristics: Habit unicaespitose, dense clump. Rhizome pachymorph, short. Culms straight, erect below, bending outward above. Young shoots conical, light green, sparsely brown-hairy; sheath margins brown ciliate; culm-leaf blades spreading and reflexed, green; emerge from July. Culm-internodes terete, (35) 40–55 cm long, green, often with narrow whitish green to cream stripes on the basal and lower culm, glabrous below, sparsely pale to brown hairy above and rough, to 4 cm in diameter [larger in mature clumps]; thick-walled on the basal and lower culm. Culm-nodes glabrous, smooth, not prominent; nodal line horizontal; sheath scar marginally protruding, with a narrow pale glabrous ring just above the sheath scar, with a narrow farinose ring just below the sheath scar; supranodal line clearly discernible, minutely ridged, about 10 mm above the nodal line, glabrous; aerial roots none. Branch-buds solitary, rotund, the first 2 or 3 basal nodes without buds. Branches 3, long, the central one much dominant in diameter, the 2 side branches smaller and subequal; branching from the lower culm or mid-culm up, unbranched on the basal culm; branching intravaginal. Culm-leaves deciduous on branched nodes of the mid-culm and upper culm, persistent on unbranched nodes of the basal and lower culm. Culm-leaf sheaths parabolic, 15–20 cm long, basally one-third as wide as long, shorter than half the length of the internode, rigid, initially green, changing to yellowish when young, light straw-colored when dry, brownish towards the margins, more or less scattered with appressed short brown hairs; apex horizontally truncate to slightly convex-truncate; margins brown ciliate. Culm-leaf auricles rim-like, ca. 11 mm long and 0.5–1 mm high, a little higher towards the ends, glabrous, entire, maroon, adnate to and contiguous with the basal margins of the blade, extending towards but not reaching the sheath margin. Culm-leaf ligule ca. 2 mm high, continuous with the apical sheath margin, brownish when young, light straw-colored when dry, lacerate, with 8–14 mm long erect fringes terminating in fine bristles. Culm-leaf blades rigid, reflexed, caducous, short-triangular on the basal and lower culm, ca. 4–5 cm long, base 1–2 cm wide, width of the junction with sheath apex ca. 1 third of the width of apex, glabrous on both surfaces (when dry), light straw-colored when dry; apex acute, sharp-pointed; margins eciliate (when dry). Foliage-leaves 8–11 per branchlet. Foliage-leaf sheaths keeled on the back, initially light green, becoming dull yellowish, glabrous or pale hispid; apex truncate. Foliage-leaf auricles low, rounded, maroon when young, with a few very short bristles. Foliage-leaf ligule 1–2 mm high, margin subentire, outer ligule a low rim, 1 mm high, glabrous. Foliage-leaf blades long-lanceolate, 30–53 × 5–7.5 cm, glabrous above, puberulent beneath, medium green above and beneath; base rounded to cuneate; apex attenuate; margins antrorsely scabrous; midvein proximally prominent on both surfaces, yellowish beneath; pseudopetiole 4–8 mm long. Flowers known, but not observed in detail; anthers maroon.
Flowering and seeding:
(1) The plant, a single clump, started gregarious flowering in January/February 2017. In mid-2017, the plant appeared to be dying from flowering, but a single culm with flowering branches survived, developed new leaves around July 2018, and stayed alive in 2020 and 2021 (July 10, 2021). Around May 2021, the plant unexpectedly developed two thin new shoots from the rhizome, and soon thereafter, two further shoots. These shoots developed into four leafy culms and reached a little over 2 m in height (August 2021). The four new culms are plain green, without striping. No signs of initiating flowering could be observed on these new culms in August, but flowering began in one of the culms as early as the following month (3 December 2021). All four new culms continued vegetative growth, including the flowering one, throughout 2022 (18 Sep. 2022).
(2) Seed-containing spikelets on the flowering plant were found in late March 2017. In more than 10% of spikelets, perhaps even more than 20%, a seed had developed; the spikelets dropped off early. A little over 100 seed-containing spikelets were harvested on 29–30 March, of which 100 were sown on 31 March 2017 and later distributed. Some seedlings developed on the ground around the mother plant, but all of the seedlings died during the dry seasons that followed, with the last seedling dying in 2020.Comments: This species has proven to recover growth after gregarious flowering.
Gigantochloa wrayi — new generation 2017
Gigantochloa wrayi (BS-0303): Flowering branch (left); spikelets containing seed (BS-0303A, center); seedlings, the 23rd day after sowing (BS-0303A, right)
Specimens: BS-0303A, BS-0303B, BS-0303C [-] (living plants), all raised from a low quantity of seeds from a single flowering plant (BS-0303), seeds collected by D. O., 29–30 Mar. 2017.
Characteristics: Culm-internodes plain green (May 2020).
Gigantochloa wrayi (BS-0303): Flowering branch
Gigantochloa wrayi (BS-0303A): Seeds
Seed weight: 3.3 g ≈ 100 dried spikelets (husk-wrapped seeds).
Seed germination: 50% of the seeds germinated by 17 Apr. 2017, which is the 17th day after sowing. 56 seeds (incl. 9 albinos) out of 100 seeds germinated by 21 Apr. 2017 (test 170331).
Flowering: A single, over 10 m tall plant started gregarious flowering Jan./Feb. 2017. More than 10% of the spikelets developed seeds. It has been expected that the clump is going to die after flowering. Actually, all culms died in 2018 except a single flowering culm, which is still alive with well-developed leaves (26 Mar. 2019, 21 July 2020, 8 Nov. 2020).
Seedling development: A few seedlings have been selected from BS-0303A (seedlings raised from 100 seeds) and potted for further observation. The remaining seedlings were handed over to ธ. บ. of Boonthammee Bamboo Garden. Furthermore, an uncountable number of seedlings have grown on the ground around the flowering mother plant. They were about 3–6 cm tall by mid-June 2017. As the site has been insufficiently irrigated during the dry and hot season, most seedlings have died, and the last seedling died in 2020. Therefore, and from observation of potted seedlings that were regularly irrigated, it is clear that the species requires moist soil conditions. A single potted seedling (BS-0303C) has been strong-growing and reached a height of 1.5 m by March 2019. A new shoot appeared in late March.
Gigantochloa wrayi (BS-0303A): Seed bare of husks (top), Germinating seeds, 17th day (bottom)
Gigantochloa wrayi (BS-0303C): 2-year-old seedling