2. 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 brown.

Distribution - 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.