Bambusa polymorpha
Bambusa polymorpha Munro, Trans. Linn. Soc. London 26 (1), 1868: 98.
Thai names: ไผ่หอม (phai hom) (Bangkok); ไผ่หอบ (phai hop) (Northern); ไผ่สะหลอน (phai sa lon) (Northern); ว่าเค๊ะ (wa-khe) (Karen: Mae Hong Son); สะลอม (sa-lom) (Shan: Northern). — T. Smitinand, 2001 [#1003]; BKF [#1368].
Distribution: THAILAND (North), native, cultivated elsewhere. — MYANMAR: native. — BANGLADESH (East), native. — INDIA (North-East), native. — Possibly also in southern China. — N. Bystriakova & al., Bamboo Biodiversity, 2003: map 14 [#1342].
Culm size: Height 10–20 (25) m, diameter 7–15 cm.
Descriptions:
(1) "A large evergreen, densely tufted bamboo; sometimes leaf-shedding in dry season. Culms 16-25 m high, 8-15 cm diameter, gray to grayish- green, white scurfy when young; nodes thick, lower ones rooted; internodes 40-60 cm long. Culm-sheaths 20-25 cm long and 30-35 cm broad, persistent, broader at base and narrowed into a rounded top, covered on back with densely and closely appressed brown to dark-brown deciduous hairs; ligule narrow, irregularly dentate, ciliate; auricles two, unequal, falcate, continuous with sheath, fringed with deciduous stiff bristles; blade 6-10 cm long, reflexed, deciduous, base triangular cordate, apex acuminate, abaxial surface with brown pubescence and adaxial surface felted with dark hairs, margins ciliate. Young shoots brownish-green. Sheath light brown, or sometimes greenish or golden yellow, covered with dark brown hairs, blades greenish with dark brown hairs; lower half margin with whitish or yellowish cilia, boatshaped, at the tip of the shoot auricles biseriate, prominent, wavy, with whitish or yellowish cilia. Leaves 7-18 cm long and 1-2 cm broad, linear-lanceolate, base obliquely rounded; petiole 2-3 mm long; ligule very thin; auricle with brown bristles. …" — K. K. Seethalakshmi & al., Bamboos of India, 1998: p. 70 [#1062].
(2) "Culms 15–20 m, 7–15 cm in diam., apically nodding; internodes gray-green, 40–65 cm, initially with white powdery chaff; wall thick; nodes slightly prominent, several basal nodes with rings of aerial roots; branching only from mid-culm up. Branches many, clustered, arched, slender. Culm sheaths quite persistent, short, broad, leathery, rigid, densely pale brown or silky white hairy, apex curved-truncate; auricles subequal, not slanted downward, projecting up or down, falcate, broadly belt-shaped, 7–8 × 2.5–3 cm, strongly wrinkled; oral setae dense, 1–1.5 cm, thick, scabrous; ligule 7–8 mm, shortly fimbriate; blade erect, nearly symmetrical, broadly lanceolate, base slightly narrowed and joined to auricles for ca. 2.5 cm, ca. 1/3 width of sheath apex, abaxially brown silky hairy, apex acute, sharply tipped. Leaf blade linear to narrowly lanceolate, 15–20 × 0.9–1.5 cm, both surfaces initially pubescent, later adaxially hairy near base and abaxially along midrib. …" — Flora of China [#1303].
(3) "… Rhizomes short; pachymorph. Culms erect; 1500–2500 cm long; 75–150 mm diam.; woody; with aerial roots from the nodes. Culm-internodes terete; 40–60 cm long; grey; distally pruinose. Culm-nodes swollen. Lateral branches dendroid. Culm-sheaths 15–18 cm long; 0.5 times as long as wide; pubescent; with appressed hairs; with white hairs; truncate at apex; auriculate; setose on shoulders. Culm-sheath blade triangular; cordate; 7.5 cm long; pubescent. Leaves cauline. Leaf-sheaths keeled; striately veined; pubescent. Leaf-sheath oral hairs scanty; deciduous. Leaf-sheath auricles falcate. Ligule an eciliate membrane. Collar with external ligule. Leaf-blade base asymmetrical; with a brief petiole-like connection to sheath; petiole 0.1 cm long. Leaf-blades persistent, or deciduous at the ligule; lanceolate; 7–17 cm long; 7–12 mm wide. Leaf-blade venation with 8–12 secondary veins. Leaf-blade surface scaberulous; rough adaxially; pubescent; hairy on both sides. Leaf-blade margins scaberulous. Leaf-blade apex acuminate; antrorsely scabrous. …" — Kew GrassBase [#1335].
(4) "Densely tufted, sympodial bamboo, sometimes deciduous. Culm erect, curving outward at the top, 15–25 m tall, 7.5–15 cm in diameter, wall 12–20 mm thick, with appressed white deciduous hairs and white wax when young, when older white-pruinose, bluish- to greyish-green; internodes 60–100 cm long; nodes thickened. Branches arising from nodes in upper half of the culm. Culm sheath 15–17.5 cm × 30–35 cm, thick, junction with blade distinctly upcurved towards middle, long persistent, with appressed white hairs on back; blade ovate-triangular, erect or slightly diverging, 12–15 cm long, strongly convex, green or purple, base decurrent band-like along apex of sheath, lower margins long ciliate, apex thorn-like, outside with appressed, white, deciduous hairs, inside glabrous; ligule 4–5 mm long, irregularly dentate, ciliate; auricles at first embracing the culm, later becoming obliquely erect, long ciliate. Leaf blade lanceolate or linear-lanceolate, 7.5–20 cm × 8–20 mm, slightly rough from minute tubercles, at first hairy on both surfaces; sheath compressed, slightly keeled at top, green; ligule very short; auricles 0.25–0.5 mm, ciliate. … [flowers described]. Caryopsis ovoid, 5 mm long, plano-convex with hairy top." — P. C. M. Jansen & S. Duriyaprapan in S. Dransfield & E. A. Widjaja (eds.), Plant Resources of South-East Asia No. 7, Bamboos, 1995: p. 67-69, fig. [#1226].
Images: Line drawing in K. K. Seethalakshmi & al., Bamboos of India, 1998: fig. 19, p. 71 [#1062]; line drawing in Flora of China [#1303]. Photo of plant in AsianFlora [#1332]; photo in K. M. Wong, Bamboo - The Amazing Grass, 2004: fig. 47 (culms) [#1048]; photos in K. K. Seethalakshmi & al., Bamboos of India, 1998: p. 70 (shoots, culms) [#1062]; photo in Y. M. Yang & al., 1998: fig. 3 (shoot) [#1213].
Uses: Culms for construction and handicrafts; young shoots for food.
Flowering cycle: 54…80 years [#1320].
Seed weight: Two different records, (1) ≈125,000 seeds/kg → ≈125 seeds/g [#1302]; and (2) 1,000 seeds ≈ 38 g → ≈26 seeds/g [#1226].
Seed viability: Unknown, viability assumed to last at least several months.
Bambusa polymorpha, Xishuangbanna Tropical Botanical Garden, Jan. 2022 — by courtesy of Lihua Jiang, Yunnan Bamboo, China
Specimen: BS-0871 [BBG] (living plant), raised from seeds; the seeds as "灰秆竹 (huī gǎn zhú) Bambusa polymorpha" from YNB, Yunnan, China, collected Dec. 2015, received 20 Apr. 2016.
Characteristics: Culm-leaf auricles large, bristly.
Seed weight: Not recorded.
Seed germination: Seeds placed on moistened tissue paper, 7 May 2016, atmospheric humidity >70%, the first coleoptiles emerged on the 2nd day, germination rate very low, ≈10% (test 160507).
Comments: The size and form of the seeds match Bambusa polymorpha. The culm-leaf sheath has developed a large bristly auricle, which could count for Bambusa polymorpha. The morphology of the seed, culm, and culm-leaf suggest that it is indeed Bambusa polymorpha.
Bambusa polymorpha (BS-0871): Seeds (left), germinating seeds on tissue paper, 14th day (right)
Specimens: BS-0913 [-] (living plant), said having been raised from seeds originating from India, the plant received as "Bambusa polymorpha" from ต. น., Nan, northern Thailand, 9 July 2016.
Characteristics: Habit unicaespitose, tight clump. Rhizome pachymorph, short. Culms straight, erect, ultimate length and diameter not yet known (about 6 m long by 3 cm in diameter in June 2021). Young shoots emerge from June. Culm-internodes terete, 40–50 (57) cm long, bluish green and with farinose fuzz when young (the fuzz can be wiped off easily), mid-green and glabrous when old; walls moderately thick. Culm-nodes glabrous, smooth, not prominent; nodal line horizontal, marginally protruding 0.5 mm; supranodal line obscure, without a ridge, ca. 7–10 mm above the nodal line; aerial roots occasionally present on basal nodes. Branch-buds solitary, subrotund to ovate, broader than tall, from the basal node up. Branches many (about 13), arched, slender, subequal, with a central branch slightly dominant; unbranched on the lower culm; branching intravaginal; rebranching. Culm-leaves early deciduous on branched nodes of the mid and upper culm, persistent on unbranched nodes of the basal and lower culm. Culm-leaf sheaths about 10 cm long, 1-fourth or shorter than the length of the internode; thickly papery, yellowish green to light green when young, light straw-colored when dry; initially with patches of very short, appressed white chaffy hairs when young, easily removable, and becoming mid to dark brown with age; margins pale ciliate when young, dark ciliate when dry; apex rounded. Culm-leaf auricles very large sickle-shaped, protruding and wrinkled lobes, mid-brown when young, with up to 10 mm long waved pale bristles. Culm-leaf ligule very short, entire, mid-brown when young. Culm-leaf blades leathery, persistent, deflexed to reflexed; broadly short-lanceolate; junction with sheath about 1-fifth of blade width; mid-brown when young and old; glabrous(?) on both surfaces; apex attenuate, sharply pointed; margins eciliate. Foliage-leaves 7–11 per branchlet. Foliage-leaf sheaths keeled, light to mid-green, glabrous; margins eciliate. Foliage-leaf auricles conspicuous sickle-shaped lobes, with up to 9 mm long straight or slightly waved pale bristles. Foliage-leaf ligule inconspicuous. Foliage-leaf blades soft, narrowly lanceolate, (12) 20 (24) × (1) 2.3 (3) cm; mid-green on both surfaces, slightly rough, almost glabrous but with a few scattered soft hairs above, puberulent beneath when young; base rounded to wedge-shaped; apex attenuate; margins antrorsely scabrous; midrib proximally prominent and light green beneath; pseudopetiole short, 0.5–1 mm.
Specimen: BS-0815 [-] (living plant), raised from seeds. The seeds collected Mar. 2015 and received as "Cephalostachyum pergracile, 香糯竹 (xiāng nuò zhú)" from FMXG, Yunnan, China, 1 July 2015.
Seed weight: 10 g ≈ 230–280 dried spikelets (husk-wrapped seeds).
Seed germination: (1) Out of 40 seeds, the first 4 seeds germinated as early as on the 2nd day after sowing, and a further 15(!) seeds on the 3rd day, with a germination rate over 60% (test 150701). — (2) Half a year later, a second test (test 160119) again showed good germination results.
Comments:
(1) After receiving the seeds (BS-0815) and judging their morphology, it was doubtful whether these seeds obtained from China are genuine Cephalostachyum pergracile (syn. Schizostachyum pergracile) because their morphology clearly differed from Cephalostachyum. Seeds of Cephalostachyum pergracile have an ellipsoid to obovoid shape, and the seed apex has a long and persistent style base.
(2) A 4-year-old seedling shows culm-leaf characteristics different from Cephalostachyum pergracile. At this early stage of the plant, it has been assumed that BS-0815 must be a different species, possibly related to Cephalostachyum pergracile. However, when the plant was six years old and the characteristics became clearer, it turned out to be Bambusa polymorpha (Lihua Jiang, Yunnan Bamboo, China, pers. comm., WeChat, 18 Jan. 2022).
Seeds (BS-0815) received from China as "Cephalostachyum pergracile, 香糯竹 (xiāng nuò zhú)"
Seeds (BS-0815) germinating, 9th day
Seeds (BS-0815) 10 months old, germinating, 24th day