Pothos lorispathus Ridl.

13. Pothos lorispathus Ridl.

Pothos lorispathus Ridl., J. Straits Br. Roy. Asiat. Soc. 86 (1922) 310 (as ‘lorispatha’). —Type: Malaysia, Selangor, Batu Caves, Ridley s.n. (fl.) (SING! holo; K! iso).

Moderate, robust heterophyllous (?) root-climbing liane to 8 m. Eocaul & juvenile shoot not observed; stem of mature sterile shoot to 6 mm diam., terete in crosse section, stem dark, glossy green, becoming brown with age, moderately clothed with leaves, eventually becoming naked, naked portions with somewhat prominent, 50 – 100 mm distant nodes, often producing long, free and adherent feeding roots, these terete with a slightly rough, occasionally minutely spiny, epidermis; fertile shoots seldom branching, stem of fertile shoot to 4 mm diam., densely clothed with leaves; foraging shoot subterete in cross section, to 1 mm diam., proximally with a few oblong cataphylls and reduced foliage-leaves but soon becoming naked with slightly prominent nodes to 100 mm distant. Leaves when fresh mid-green adaxially, slightly paler abaxially, stiffly but thinly chartaceous, air drying dull greenish; petiole 30 – 70 mm long, slender, sheath somewhat prominent, extending to just below geniculum, basally clasping, apically briefly auriculate to slightly ligulate; lamina 100 – 340 x 25 – 100 mm, oblong-elliptic, often falcate, unequal, occasionally quite strongly so, with 2 intramarginal veins per side, the lowermost arising from the base, the next arising from the lowest part of the midrib, outer intramarginal vein remaining very close and parallel to margin, inner vein c.10 mm distant, both reaching the leaf tip, base rounded, apex acute to acuminate, very briefly tubulate. Flowering shoot abbreviated, usually leafless but with 1 – several well-developed cataphylls, very occasionally with one or more fully developed but reduced leaves, arising from below the leaf axils of fertile shoots. Inflorescence solitary but flowering shoots almost always reiterating and thus several inflorescences at varying degrees of developmental maturity often present; peduncle 27 – 50 x 2 – 3 mm, moderately stout, erect or curving and ultimately ascending and the inflorescence held erect, dull green; spathe 25 – 100 x 5 – 15 mm, lorate, spreading, base auriculate, auricle margins inrolled, barely decurrent on the peduncle, apex obtuse, acuminate, mid-green; spadix stipitate; stipe 8 – 15 x c. 2 mm, slender, terete, lime green; fertile portion 50 – 65 x 3 – 4 mm, cylindrical to tapering slender–cylindrical, straight to slightly curved, base unequal, slightly cochleate, creamy-yellow. Flowers c. 1.5 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform, pale yellow, apex slightly fornicate, triangular, truncate, margins minutely reflexed; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae c. 0.2 mm diam, pale yellow; ovary 1 – 1.5 x 0.25 – 0.75 mm, compressed globose, yellow-green; stylar region rounded; stigma punctiform. Infructescence with numerous berries; fruit 10 – 15 x 5 – 8 mm, obclavate to ellipsoid, ripening deep scarlet, with basal chartaceous tepal remains, stigmatic remnant tiny, on a flattened stylar region. Seeds c. 4 – 6 x 2 – 4 mm, ellipsoid.

Distribution — Peninsular Malaysia, Thailand. Specimens from Sabah and Sarawak may be referable to P. lorispathus or may represent an undescribed species.

Habitat & Ecology — Damp to rather dry evergreen hill forest on limestone and granite. 50 – 100 m.

Notes — In the review area P. lorispathus is known only from Yala province, Thailand, where it occurs on limestone and granite. Originally described from the Batu Caves, Selangor, Malaysia, P. lorispathus it has seldom been recollected and is known from very few specimens.
Although strerile specimens are very difficult to distinguish, fertile specimens are instantly recognizeable by the size and colour of the inflorescences; there are no other large green-inflorescenced Pothos in the review area. Pothos lorispathus is superficially similar to P. lancifolius but readily distinguishable by the lorate spathe, stipitate spadix and slender (not thickened) peduncle.

Geographically representative selection of collections studied:
THAILAND. PEN75. Yala: Bang Lang N.P, 006° 12’N, 101° 10’E, 30 March 1997, Boyce 1218 (fl, fr.) (BKF, K and K Spirit Coll. no. 63296).