Schizostachyum pergracile
Schizostachyum pergracile (Munro) R. B. Majumdar, in S. Karthikeyan & al., Fl. Ind. Enumerat., Monocot., 1989: 282.
Synonym: Cephalostachyum pergracile Munro, Trans. Linn. Soc. London 26 (1), 1868: 141.
Thai names: ไผ่ข้าวหลาม (phai khao lam; a frequent spelling variant of the Romanized Thai name is "kao larm"); ไผ่ข้าวหลามกาบแดง (phai khao lam kap daeng); ขุยป้าง (khui pang) (Chiang Mai); ป้าง (pang) (Northern); ว่าบลอ (wa-blo) (Karen: Mae Hong Son); ว่าพล้อง (wa-phlong) (Karen: Kanchanaburi). — T. Smitinand, 2001 [#1003]; BKF [#1368].
Chinese name: 香糯竹 (xiāng nuò zhú).
Distribution: THAILAND (North, North-East, West, South), in evergreen, mixed evergreen, mixed deciduous, and bamboo forest, at 50–700 m altitude; frequent and widespread, but is said to have become rare in some regions due to excessive exploitation. — MYANMAR, common and widespread, in mixed deciduous forests. — LAOS. — BANGLADESH. — INDIA (North-East, East, South). — NEPAL. — CHINA (South). — VIETNAM (North). — N. Bystriakova & al., Bamboo Biodiversity, 2003: map 19 [#1342].
Local distribution: Planted in villages in the Chiang Mai area, infrequent. Not found offered for sale at Kham Thiang Market, Chiang Mai.
Culm size: Height 5–15 (18) m, diameter 5–8 (9.5) cm.
Descriptions:
(1) "Tufted, deciduous, sympodial bamboo. Culm erect with pendulous tip, 7–30 m tall, 2.5–7.5 cm in diameter, wall very thin, glaucous green, somewhat whitish puberulous below the nodes; internodes 20–45 cm long; nodes slightly thickened. Branches arising from the higher nodes, many at each node, about equal in size. Culm sheath 10–15 cm × 15–20 cm, thick and leathery, promptly or tardily deciduous, reddish-brown, shiny, usually covered with appressed, blackish, stiff, deciduous hairs toward the base; blade ovate, cordate, cuspidate, 5 cm long, about half as wide as apex of sheath, densely hirsute on adaxial surface; ligule very narrow, 1.5–2 mm long, entire, densely white ciliolate; auricles horizontally extending along the top of the sheath, linear-lanceolate, 3–4 mm wide, densely wavy-bristly along the margins. Leaf blade linear-lanceolate, 10–35 cm × 1.5–6.0 cm, rought on both surfaces and margins sparsely puberulent beneath; sheath faintly striate, glabrous, ending in a small ciliate callus; ligule very low, entire; auricles usually lacking, leaving 2–3 early caducous, white, long bristles. … [flowers and seeds described]." — S. Duriyaprapan & P. C. M. Jansen in S. Dransfield & E. A. Widjaja (eds.), Plant Resources of South-East Asia No. 7, Bamboos, 1995: p. 78-80, fig., as "Cephalostachyum pergracile" [#1226].
(2) Kew GrassBase, as "Cephalostachyum pergracile" [#1335].
(3) K. K. Seethalakshmi & al., Bamboos of India, 1998: p. 252 [#1062].
(4) Flora of China, as "Cephalostachyum pergracile" [#1303].
Images: Line drawing in Bamboos of India, 1998: fig. 88, p. 253; in Flora of China [#1303]; photos in AsianFlora [#1332]; photos by Niramit Sareerudt on Facebook, 26 Jan. 2014; Flowering of Schizostachyum pergracile in Nan, photos on Facebook, 25 Oct. 2020, by เตี๋ยวโฟ แซ่บเว่อร์; flowering of Schizostachyum pergracile in Nan, photos on Facebook, 26 Dec. 2020, by Jeera Makmee.
Uses: Culm sections are used as a flavor-adding cooking vessel for a Thai sticky rice dish called ข้าวหลาม (khao lam); culms are used for roof frames, basketry, handicrafts (lacquerware); plants used as garden ornamentals, for privacy screening, as windbreaks, and in landscaping; shoots edible.
Cultivation requirements: Easy-growing on heavy moist soil in full sun or partial shade.
Flowering cycle: Unknown, although gregarious flowering is known. In Thailand, gregarious flowering occurred in 1987, with a large amount of seed production. It has been reported that the species can sporadically flower almost every year, generally without producing seeds [#1226]. For a period of more than 15 years, plants of Schizostachyum pergracile grown at Bambusetum Baan Sammi have not shown signs of initiating flowering.
Seed viability: 10 months and longer without cool storage.
Comments:
(1) Based on a molecular study and morphological comparison, Schizostachyum pergracile forms a subclade, together with Schizostachyum brachycladum, S. zollingeri, and S. virgatum, within the clade Schizostachyum s.str. (H. Q. Yang, S. Peng & D. Z. Li, Generic delimitations of Schizostachyum and its allies …, Taxon 56(1), 2007: 45-54 [#1013]).
(2) "On the basis of papillae characters, Schizostachyum s.s. and Cephalostachyum were confirmed … Cephalostachyum virgatum and C. pergracile were confirmed to be members of Schizostachyum s.s." (H. Q. Yang, H. Wang & D. Z. Li, Comparative morphology of the foliage leaf epidermis, with emphasis on papillae characters …, Bot. J. Linnean Soc., 156(3), 2008: 411-423 [#1012]).
Schizostachyum pergracile (BS-0182): An old culm (left), and a new culm with a culm-leaf (right)
Specimen: BS-0182 [C5] [W1] (living plants), A. Doi Saket, Chiang Mai, cult., received as ไผ่ข้าวหลาม (phai khao lam), June 2003.
Characteristics: Habit tight caespitose. Rhizomes pachymorph, short-necked. Culms erect, slightly bending outwards above (→ table with culm size dimensions). Young shoots orange-yellow. Culm-internodes terete, farinose and bluish-green when young, green and glabrous with maturity, thin-walled. Culm-nodes not prominent, glabrous, the basal nodes without aerial roots. Branch-buds solitary. Branches many, thin, subequal, short, 0.5–1 m long, usually not rebranching; often without branches on the lower culm, but occasionally with rudimentary branches on the lower culm; branching extravaginal; nodes of branches rather prominent. Culm-leaves persistent, decaying on the culm or dropping off late. Culm-leaf sheath coriaceous, abaxial surface glossy orange-yellow, glabrous, but lower part with dense appressed blackish hairs. Culm-leaf auricles broad and low, adnate to and contiguous with the basal margin of the blade, extending along the sheath apex and protruding the sheath margin; oral setae long, white, numerous, irregularly waved. Culm-leaf ligule broad, very low, entire. Culm-leaf blades coriaceous, large, long triangle-shaped, sharply pointed, not reflexed but somewhat bent outwards, lower adaxial surface densely covered with short dark hairs; margins convolute. Foliage-leaves 5–8 per branchlet. Foliage-leaf sheaths glabrous, orange-yellow. Foliage-leaf blades medium-sized, long and narrow, green, glabrous on both surfaces, usually 15–28 cm long, 15–25 (30) mm wide.
Specimens: BS-0387 [†] (= HHK-012) (living plant), Royal Project, Huai Hong Khrai (ห้วยฮ่องไคร้) Study Center, A. Doi Saket, Chiang Mai Province, cult., received as ไผ่ข้าวหลาม (phai khao lam) via ธ. ล., 11 Dec. 2009; BS-0387A [N2] (living plant), seedling, raised from seeds, collected by D. O., Jan. – Mar. 2012, from a single flowering plant (BS-0387) grown at Bambusetum Baan Sammi.
Seed weight: 10 g ≈ 400–440 dried spikelets (husk-wrapped seeds).
Seed germination: Seeds with only ripe big seeds, sown in Mar. 2012, showed a high germination rate (>60%).
Comments: Nearly all spikelets consisted of empty florets, and seeds developed very rarely.
Specimen: BS-0691 [BBG] (living plant), raised from seeds collected by ธ. ล. from cultivated flowering plants at Mae Suai (แม่สรวย) District, Chiang Rai Province, northern Thailand, in Jan. and Feb. 2012, received as ไผ่ข้าวหลาม (phai khao lam), 14 Jan. and 24 Feb. 2012.
Seed weight: 10 g ≈ 400–440 dried spikelets (husk-wrapped seeds).
Seed germination: Seeds laid on moistened tissue paper on 26 Feb. 2012, the first shoot emerged after 9 days, 29–31 °C day temperature, diffuse light, 15–17 °C night temperature, atmospheric humidity >70%, germination rate rather low (<20%), possibly due to a large portion of unripe seeds.
Comments: Seeds were collected from gregariously flowering plants; nearly all spikelets consisted of empty florets, and seeds developed very rarely.
Schizostachyum pergracile: Flowering branches (BS-0691)
Schizostachyum pergracile: Seeds (BS-0691)
Schizostachyum pergracile (BS-0691): Germinating seed on tissue paper, 10th day
Schizostachyum pergracile (BS-0691): 17-month-old seedling
Specimen: BS-0882 [BBG] (living plants), raised from seeds received as "Cephalostachyum pergracile, ไผ่ข้าวหลาม (phai khao lam)", collected from cultivated plants at ป่าแดด Pa Daet Subdistrict, Mueang District, Chiang Mai Province, northern Thailand, by ธ. บ., 25 Apr. 2016, received 26 Apr. 2016.
Seed weight: 0.35 g ≈ 25 dried spikelets (husk-wrapped seeds).
Seed germination: Test 160427: 16 of 25 seeds germinated.
Comments: Judging from the seed morphology, these seeds (BS-0882) seem to be genuine Schizostachyum pergracile (syn. Cephalostachyum pergracile). Seedlings raised were moved to Boonthammee Bamboo Garden, Hang Dong, in 2016.
Schizostachyum pergracile (BS-0882): Seeds with husks
Schizostachyum pergracile (BS-0882): One seed, bare of husks
Schizostachyum pergracile (BS-0882): Seedlings, 24th day
Specimen: BS-0872 [BBG] (living plants), raised from seeds received as "Cephalostachyum pergracile, 香糯竹 (xiāng nuò zhú)" from FMXG, Yunnan, China, 20 Apr. 2016, collected Jan. 2016.
Seed weight: Not recorded.
Seed germination: Test 160420: 9 of 25 seeds germinated.
Comments: Judging from the seed morphology, these seeds (BS-0872) received from China seem to be genuine Schizostachyum pergracile (syn. Cephalostachyum pergracile). Seedlings raised were moved to Boonthammee Bamboo Garden, Hang Dong, in 2016.
Schizostachyum pergracile (BS-0872): Seeds
Schizostachyum pergracile (BS-0872): Seedlings, 18th day