Epipremnum falcifolium Engl.
Epipremnum falcifolium Engl., Bot. Jahrb.
Syst. 25 (1898) 11; Engl. & K. Krause in Engl., Pflanzenr. 37
(IV.23B) (1908) 58. -- Type: cultivated Bogor Botanic Garden, Canarienallee
Z65, 1906, Engler s.n. (BO holo; B & spirit B iso).
Very large root-climber to 15 m. Pre-adult plant forming extensive
terrestrial colonies. Adult plant with stem 5--30 mm diam., internodes
0.5--13 cm long, separated by prominent pale leaf scars. Growing
stems smooth, glossy dark green, older stems sub-woody, mid-brown.
Slender flagellate foraging shoots occasionally occurring, these
moderately to very long (7 m or more). Clasping roots sparse, minutely
pubescent, later corky, mid- to dark brown, growing tip pale brown-yellow,
strongly adherent to substrate. Cataphylls and prophylls soon drying
and falling. Foliage leaves evenly distributed, lower leaves falling
and thus leaves tending to become clustered distally. Petiole 25--80
cm x 5--20 mm, canaliculate, smooth, dark green, air-drying pale
to dark brown; apical geniculum 15--35 x 2--5 mm, basal geniculum
7 x 1--1.5 cm, both genicula greater in diameter than petiole, drying
shrunken to less than petiole diameter and darker; petiolar sheath
extending 2/3--3/4 along petiole, at first sub-membranaceous, soon
drying scarious, later disintegrating in regular blocks and then
falling to leave a somewhat roughened, mid-brown scar. Lamina 5--58
x 3--20 cm, entire, oblique-elliptic, slightly falcate, sub-coriaceous
to coriaceous, apex acute, base unequal-rounded, lustrous dark green,
air-drying strongly discolorous with adaxial surface deep black-brown,
abaxial surface pale to mid-red-brown; primary lateral veins simple,
c. 30 per side, c. 1 cm distant, diverging from midrib at 40°--60°,
interprimary veins remaining sub-parallel to primary vein, all higher
order venation conspicuously tesselate in dried material; midrib
impressed above, very prominently raised beneath, lower order venation
slightly impressed to almost flush above, variously raised beneath,
higher order venation flush above, flush or nearly so beneath in
fresh material but raised and rather conspicuous in dried specimens.
Inflorescence solitary, subtended by a fully developed foliage leaf
with an exceptionally broad petiolar sheath. Peduncle 5--10 cm x
4--12 mm, stout, terete, tapering basally, pale green. Spathe canoe-shaped,
stoutly beaked, stiffly coriaceous, gaping at anthesis, up to 27
x 10 cm when pressed flat, exterior green, later dull yellow, interior
dull yellow at anthesis, air-drying mid-brown to almost black. Spadix
17--24 x 3--5 cm, sessile, cylindrical, bluntly tapering towards
the apex, dark yellow at anthesis, air-drying mid-brown. Flowers
4--12 mm diam., the uppermost flowers on the spadix partially fused
and sterile; stamens 4; filaments 5 x 1 mm; anthers narrowly ellipsoid,
3--5 x 0.75--1 mm; ovary 7--12 x 3--8 mm, cylindrical-ellipsoid,
basal part strongly compressed; ovules 2; stylar region 4--12 x
1.5--4 mm, trapezoid, often misshapen by lateral compression of
other styles, exceptionally robust, apex flattened, margins strongly
reflexed in dry material; stigma linear with two prominent lateral
cushions, 2--6 x 0.1--0.5 mm, longitudinal. Fruit light-green, ripening
red, stylar region greatly enlarged, the region surrounding the
stigma swollen and the stigma thus raised; ovary cavity with the
seeds embedded in sticky red pulp. Seeds curved, c. 5 x 4 mm, pale
- Brunei, Malaysia (Sabah) and Indonesia (Kalimantan).
Habitat - Near
rivers, mixed dipterocarp forest, swampy secondary forest, Setap
shales, clay soil, yellow sandy loam. 5--250 m.
Notes - 1. Described
from plants of doubtful origin grown at Bogor Botanic Garden, the
provenance of E. falcifolium was unknown until recent collections
from Brunei. During the preparation of this revision searches in
various herbaria revealed several hitherto undetermined collections
by Kostermans [Kostermans 10560 (Kalimantan; BO!, L!)], Hotta [(Hotta
13324 (Brunei; KYO!)], Kokawa & Hotta 263 [Sabah; KYO!, L!]
and Mariyoh & Lideh [(SAN 111746 (Sabah; E!, K!, SAN!)].
2. Epipremnum falcifolium and E.
giganteum have similar infructescences with massively enlarged
stylar tissue but they can usually be readily separated on leaf
characters (see Key to species above). However, Alston 12632 &
15465 approach E. giganteum in appearance. Nevertheless, the living
plants still at Bogor are unquestionably E. falcifolium (Boyce,
pers. obs., 1996). Dried inflorescences and infructescences of E.
falcifolium have the region around stigma expanded into two
lateral cusions (see Fig. 2). These are absent from E. giganteum
(see Fig. 3).
3. Epipremnum falcifolium often produces fruits with a solitary
seed by abortion, q.v. E. ceramense.