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Description
Culms 5 – 20 m tall, 1.2 – 4.0 cm in diameter; young culms
glaucous, with a white waxy ring below each node; inter-
nodes 10 – 25 cm long, with walls thin, 2.5 – 3.0(
5.0) mm
thick (mid-culm portion). Branches developing from the
lower quarter or from around the mid-culm upwards.
Culm leaves 8 – 13 cm long
10 – 15 cm wide, at top
shallowly convex to truncate, on back covered with thick
white wax and appressed black hairs; blades narrowly
triangular, erect, slightly infl
ated at base, often slightly wavy,
9 – 20 cm long, 4.5 – 6.0 cm wide near the base; auricles
small lobes, 0.5 – 1.0 mm tall, fragile, bearing curved fi
m-
briae; ligules 0.5 – 1.0 mm tall, with margin irregularly
denticulate. Leaves 5 – 9 per branchlet; blade 15 – 30 cm
long
2 – 5 cm wide, glabrous, occasionally sparsely hairy
near the base, rounded to acute or attenuate at base, acumi-
nate at apex; pseudo-petiole 0.2 – 0.5 cm long; leaf sheaths
3 – 6 cm long, puberulous, with hairy margins; auricles
tiny falcate lobes, with margins fringed with bristles up to
1 cm long, sometimes absent; ligules ca 0.5 mm high, irregu-
larly toothed along margin. Pseudo-spikelets 1.5 – 2.5 cm
long; subtending bract chartaceous, ca 4 mm long, sparsely
hairy on back. Spikelets 0.5 – 1.2 cm long; glume 1, charta-
ceous, 3 – 4 mm long, mucronate, with ciliate margins,
5 – 7-nerved; lemmas similar to glume, 4 – 5 mm long;
paleas chartaceous, 4 – 5 mm long, 2-keeled, keels ciliate,
2-nerved between keels and 3-nerved on each involute
margin; lodicules membranaceous, 3(4 – 5), ciliate. Anthers
3.0 – 3.5 mm long; fi
laments free; anther apices mucronate
(the connective prolonged beyond the anther apex), gla-
brous. Fruits compressed globose, 4 – 5 mm.
Distribution and habitat
Th
e geographic range of
P. polymorphum
is from tropical to
temperate Asia. It is found in highland areas (900 – 1500 m
a.s.l.) of India, Bhutan, China, Burma and Vietnam
(Stapleton 1994, Ohrnberger 1999, Xia and Stapleton
2006). We have discovered four additional populations
of
P. polymorphum
in Th
ailand living at altitudes of
900 – 1300 m a.s.l. in Phu Rua National Park, Phu Luang
Wildlife Santuary, Phu Kradung National Park, Loei pro-
vince and Phu Hin Rong Kla National Park, Phitsanulok
province. Th
is species inhabits only semi-shaded areas, forest
edges and gaps of lower montane forest.
Notes
Th
e specimens examined from Th
ailand diff
er from the
Indian material of Munro (1868) and Gamble (1896)
mostly in the number of fertile fl
orets. Th
e Th
ai specimens
have two fertile and one vestigial fl
oret, and they diff
er in
having three lodicules and stigmas. Th
e Indian specimens
were described as having one fertile fl
oret and a tendency
to have four lodicules and two stigmas. However, the
general morphology of the specimens is consistent with
P. polymorphum
. We feel these slight morphological dif-
ferences, with the present available material, are insuffi
cient
to separate them into species, subspecies or varieties.
Camus (1913) referred the Burmese bamboo named
‘ Wakha ’ to
P. wakha
. Th
e protologue was established
on Brandis description, which was based on C. B. Smales
collection (Smales s.n.) from Hmangin Village, Burma.
Among the given characters, Camus (1913) and Brandis
(1906) indicated that
P. wakha
is similar to
P. polymorphum
but diff
ers in having tufted culms. According to our
observations, there are no apparent diff
erences between the
species. In addition, we also found that the sterile parts
of our
P. polymorphum
fl
owering specimens are very similar
to the description of Brandis (1906) and Camus (1913).
Additional specimens examined
India, Assam, Griffi
th 1394 (BM), Griffi
th 1395 (BM),
Griffi
th 1397 (BM), Griffi
th 1403 (BM); Nigrigam, 18 Jan
1836, Griffi
th 6735 (K); Sikkim, Hooker s.n. (K), Aug 1828,
Hooker s.n. (K); Latpanchar, 610 m a.s.l. (2000 ft), 3 May
1871, Gammie s.n. (BM). Th
ailand, Phitsanulok: Phu
Hin Rong Kla, 1319 m a.s.l., 9 Jul 2011, A. Teerawatananon
and S. Sungkaew 1430 (Nat. Hist. Mus. Th
ailand); Loei:
Phu Luang Wildlife Sanctuary, 1000 m a.s.l., 12 Aug 2004,
S. Sungkaew and A. Teerawatananon 176 (Nat. Hist. Mus.
Th
ailand); Phu Rua National Park, 900 m a.s.l., 18 Jun
2010, A. Teerawatananon and S. Sungkaew 1102 (Nat.
Hist. Mus. Th
ailand).
Acknowledgements – | en |
