The genus Trichosanthes L. (Cucurbitaceae) in Thailand ...

THE GENUS TRICHOSANTHES L. (CUCURBITACEAE) IN THAILAND (B.E.E. DUYFJES & K. PRUESAPAN) 97
Vernacular.— Tum ka (ตูมกา), khi ka yai (ขี้กาใหญ),
khi ka khorn (ขี้กาขอน),
kra
dueng chang (กระดึงชาง), luk khi ka (ลูกขี้กา),
buap liam (บวบเหลี่ยม)
(Geranal).
13. Trichosanthes siamensis Duyfjes & Pruesapan, sp. nov. Trichosanthi ovigera folii
margine minute dentato fructu longitudinaliter pallide lineato similis, foliis infra glabris,
seminibus crassis laevibus nec cupiformibus cingulo lato distincta. Typus: Thailand,
Kanchanaburi, Thung Yai Naresuan Wildlife Sanctuary, Maxwell 94-546 (holotypus L;
isotypus L).
Climber, several metres long; monoecious (see note); subglabrous, hairs shaggy,
0.5 mm long, largely early glabrescent; plant green, blackish on drying, the petals white;
cystoliths not obvious; stem 2(–3) mm diam. Probracts absent. Tendrils simple. Leaves:
blade unlobed or deeply 3–5-lobed to ¾, the lower lobes straight and downwards
directed, membranous, (sub)glabrous; ovate or suborbicular in outline, 7–15 by 5–12
cm, base deeply cordate with narrow or broad sinus, or (sub)hastate, mid-lobe to 13 by
2.5 cm, the apex acute-acuminate, the margin entire or finely serrate-dentate; glands
absent; petiole 1.5–4.5 cm long. Male raceme 12–14 cm long, (densely) minutely brown
hairy, sometimes co-axillary with a solitary flower; peduncle 3–4 cm long, 1.5–2 mm
thick; rachis with 15–20 flowers; bracts late caducous, chartaceous, subovate, 9–10 by
4–5 mm, with glands, the margin serrate-lobed. Male flowers: greyish hairy, glabrescent;
pedicel caducous, ca. 5 mm long (10–20 mm long in solitary flower); perianth immature,
presumably as in female flowers; synandrium ca. 6 mm long, the filaments ca. 3 mm
long, subglabrous Female flowers: pedicel ca. 15 mm long; ovary narrowly ellipsoid,
much narrowed towards apex, ca. 10 by 2.5 mm, glabrous; receptacle tube 15–25 mm
long, at apex ca. 4 mm wide; sepals long-triangular or linear, ca. 10 mm long, 1–1.5 mm
wide, with glands, margin entire; petals ca. 12 mm long, threads ca. 6 mm long. Fruits
green with whitish longitudinal streaks, ovoid, (narrowly) ellipsoid, narrowed at both
ends, especially at apex, 7.5–9 by 3.5–4 cm; exocarp leathery, smooth; pulp unknown;
fruiting pedicel 1.5–2.5 by 0.3 cm. Seeds (from detached material) pale brown,
slightly compressed, ovoid-ellipsoid, 11–13 by 7–8 by 5 mm, the apex narrowly, the
base broadly obtuse, smooth, the margin absent, edge entire.
Thailand.— SOUTH-WESTERN: Kanchanaburi (Sangkhla Buri, Thung Yai
Naresuan Wildlife Sanctuary, Maxwell 94-546-type).
Distribution.— Endemic to Thailand and known only from the type.
Ecology.— Open or partly shaded, degraded, deciduous forest with much bamboo
on rugged limestone area, at 400 m altitude.
Vernacular.— Bai khai tha (ใบไขทา) (Karen).
Note.— The two duplicate specimens seen of Maxwell 94-546, represent male
flowering and fruiting material, either mounted on the same sheet, or female flowers
and fruits on another sheet, but male and female are not connected. However, the plant
is likely monoecious.
Field-notes.— Fruit light green with whitish-greyish vertical streaks. Leaves
polymorphic, entire or lobed.