Pothos lancifolius Hook.f.

12. Pothos lancifolius Hook.f..

Pothos lancifolius Hook.f., Fl. Brit. Ind. 6 (1893) 554; Engl. in Engl., Pflanzenr. 21 (IV.23B) (1905) 40. — Type: Malaysia, Perak (probably Bk Larut), Scortechini 576 (fl.) (K! holo; SING! iso). Pothos penicilligerGagnep., Notul. Syst. 9 (1941) 135, syn. nov. — Type: Vietnam, Col des Nuages, near Tourane (modern Danang), Poilane 8089 (fl.) (P! holo; GH!, SAI! iso),

Moderate, slender to somewhat robust heterophyllous root-climbing liane to 4 m. Eocaul not observed; stem of juvenile shoot to 3 mm diam., terete in cross section, shingle-leaved; stem of mature sterile shoot to 6 mm diam., terete in cross section, mid-green, becoming brown with age, densely clothed with leaves, but stems eventually becoming naked, naked portions with prominent, 50 – 80 mm distant nodes, often producing long, adherent feeding roots, these strongly flattened with a prominently warty epidermis; stem of fertile shoot to 4 mm diam., terete in cross section, densely clothed with leaves. Leaves when fresh mid-green adaxially, slightly paler abaxially, stiffly chartaceous, air drying dull greenish brown, midrib paler, prominently raised; petiole 40 – 140 x 1.5 – 2 mm, slender, sheath rather prominent, extending to just below geniculum, basally clasping, apically briefly ligulate; lamina 100 – 250 x 25 – 100 mm, ovate to elliptic or narrowly lanceolate, with 2 intramarginal veins per side, the lowermost arising from the base, the next arising from the lower part of the midrib, outer intramarginal vein remaining very close and parallel to margin, inner vein c.5 mm distant, both reaching the leaf tip, base rounded, apex long-attenuate, attenuate or acute, minutely tubulate. Flowering shoot abbreviated, leafy, arising from most of the mid- to distal leaf axils of fertile shoots. Inflorescence solitary, occasionally paired; peduncle, 15 – 50 x 1.5 – 3 mm, stout, spreading, dull greenish yellow; spathe 25 – 100 x 10 – 40 mm, lanceolate, slightly cucullate, base barely decurrent on the peduncle, apex acuminate, green to purplish-green, slightly softly-leathery; spadix sessile, 15 – 50 x 3 – 9 mm, cylindrical, dark to yellow-green. Flowers c. 1.5 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform, green, apex slightly fornicate, triangular, truncate; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae c. 0.2 mm diam, creamy-yellow; ovary 1 – 1.5 x 0.25 – 0.75 mm, compressed angular-ellipsoid, green; stylar region turbinate; stigma disc-like, prominent. Infructescence with numerous berries, mostly born towards the bottom of the spadix; fruit 10 – 15 x 10 – 11 mm, ellipsoid-bottle-shaped, ripening deep scarlet, with prominent basal leathery and chartaceous tepal remains and a large stigmatic remnant. Seeds c. 4 – 6 x 2 – 3 mm diam., ellipsoid.

Distribution — Peninsular Malaysia, Vietnam.

Habitat & Ecology — Degraded dry to damp seasonal evergreen hill forest on clay soils over granite. 750 – 1300 m.

Notes — The type of P. penicilliger is an exceptionally robust specimen of P. lancifolius, a species hitherto considered to be restricted to Peninsular Malaysia. Despite the dimensions of the type, other Vietnamese collections of ‘P. penicilliger’ seen match very well typical P. lancifolius. I have no hesitation is assigning P. penicilliger to Hooker’s earlier name.
Pothos lancifolius is morphologically most similar to P. kingii. It may be distinguished from P. kingii by the lanceolate, not cucullate, spathe and the bottle-shaped fruits with large, broad, stigmatic remains. Confusion may occur with the seldom-collected P. touranensis from which fertile P. lancifolius is distinguishable by the smaller inflorescences carried on much shorter peduncles; see P. touranesis for further discussion of this character. Confusion is also possible with P. lorispathus, from which P. lancifolius may be separated by the lanceolate (versus lorate) spathe, the sessile spadix and the bottle-shaped (versus ovoid, obtuse) fruits.

Geographically representative selection of collections studied:
VIETNAM. Gia Lai: K'Bang, Son Lang, 17 June1988, Vu Xuan Phuong 1190 (fl.) (HN). Quang Nam – Da Nang: Col des Nuages, 18 Sept. 1923, Poilane 8089 (fl.) (type of Pothos penicilliger , P holo, GH, MO, SAI iso).