14. Pothos touranensis
Gagnep., Notul. Syst. 9 (1941) 136; Gagnep. in Lecomte, Fl. Gén.lIndo-Chine,
6 (1942) 1082 1090; P.H. HÈ, CâaycÀ Vi_tnam
[Ill. Fl. Vietnam in Vietnamese & English], 3(1) (1993)
420 423, pl.8262. Type: Vietnam, Lien-chieu, near
Tourane (modern Danang), 19 Aug.1923, Poilane 7643 (fl.) (P! holo).
Moderately robust heterophyllous (?) root-climbing liane to 7 m.
Eocaul not observed; stem of juvenile shoot to 2 mm diam, flexuous,
terete in cross section, producing adherent flattened feeding roots;
stem of fertile shoot to 5 mm diam., terete in cross section, mid-green
to brown in dried material, leaves scattered, spreading. Leaves
brownish green to yellow-brown in dried material; petiole 80
150 x 4 11 mm, canaliculate, rounded abaxially, narrowing
towards geniculum, base decurrent, apex prominently geniculate,
geniculum at first smooth, later corky, sheath very prominent, apically
pronounced-ligulate, especially in young growth, sheath extending
to geniculum; lamina 130 200 x 50 85 mm, broadly to
narrowly oblong elliptic, 2 intramarginal veins per side, 1
15 mm from lamina margin, arising from just above base of the midrib,
remaining ± parallel to margin, terminating at the tip of
the lamina, base obtuse to broadly rounded, apex acuminate to long-acuminate,
apiculate. Flowering shoot (always?) contiguous with fertile shoot,
inflorescence (always?) terminal on a leafy fertile/flowering shoot.
Inflorescence solitary; peduncle 100 190 x c. 2 mm, robust,
curving or straight, occasionally strongly bent basally, the inflorescence
held erect, drying dark brown; spathe 60 90 x 15 20
mm, triangular, base rounded to truncate, decurrent on peduncle,
apex acuminate; spadix stipitate; stipe 10 15 x 1
2 mm, stout, terete; fertile portion 35 55 x 3 4 mm,
tapering-cylindric. Flowers 1.5 3.1 mm. diam; tepals, broadly
ovate to fornicate, 1.5 x c. 1 mm; stamens 0.75 x c. 0.5 mm, filaments
strap-shaped, thecae 0.25 x 0.25 mm, oblong ellipsoid; ovary 0.5
x 1.25 mm, compressed-globose to hexagonal-turbinate; stylar region
large, truncate; stigma small, punctiform. Infructescence with few
fruits; berries (immature) c. 2 x 3.5 mm, obturbinate.
Habitat & Ecology Rather dry mixed hill forest
on granite, on trees in very rocky soil. 700 750m.
Notes An extraordinary species, immediately recognizable
in Indochina by the immensely long peduncle a character otherwise
unknown in the review area but present in, e.g. P. mirabilis Merr.
(Borneo) and P. tener Wall. (Borneo, Sumatera). Very few collections
of P. touranensis have been made and, as with P.
gigantipes, this seems to reflect natural rarity rather
Geographically representative selection of collections studied:
VIETNAM. Khanh Hoa: Nha Trang, Co Inh massif, 17 Sept. 1922, Poilane
4593 (fl.) (P). Quang Nam Da Nang: Lien Chien, 19 Aug.1923,
Poilane 7643 (fl.) (type of Pothos touranensis,