3. Pothos gigantipes

3. Pothos gigantipes Buchet ex P.C. Boyce, sp. nov.
[P. gigantipes Buchet apud Gagnep. in Lecomte, Fl. Gén. l’Indo-Chine 6: 1085 (1942), nom. invalid. sine descr. Latin.; P.H. HÈ, Cây-cÀ Miê__ Nam Vi_t-nam [Fl. South Vietnam – in Vietnamese] (1960) 690, pl.267, D & CâaycÀ Vi_tnam [Ill. Fl. Vietnam – in Vietnamese & English], 3(1) (1993) 421, pl.8254]

Pothos gigantipes inter plures una species subgeneris typici Indochinensis inflorescentiis pedunculis longis, stipite longo atque spadice fertili globoso, ovoidea vel cylindrico est; ab omnibus speciebus ceteris subgeneris typici regionis combinatione inflorescentiis ceraceis albis et luteis, laminis adultis ellipticis atque surculis iuvenilibus caulibus compresse rectangularibus, angulis alatis, foliis insigniter venetis vel glaucis distinguitur. — Typus: Chevalier 37045 (P! holo), Vietnam, Thua Thien Hue: Thua Luu F.D.

Moderate to large, rather robust homeophyllous root-climbing liane to 4 m. Eocaul not observed; stem of juvenile shoot to 3 mm diam., strongly compressed-rectangular in cross section, the angles minutely to rather prominently winged, leaves ± congested, blue- to grey-green; stem of mature sterile shoot to 6 mm diam., mid- to dark green, becoming brown with age, slightly to strongly compressed-rectangular in cross section, at first somewhat densely clothed with leaves, stems eventually becoming naked, naked portions with prominent nodes, stem of fertile shoot to 4 mm diam., straight to somewhat zigzagging, compressed-rectangular in cross section, somewhat prominently angled, the angles winged, mostly densely clothed with leaves, older portions naked at for approximately half their length, naked portions with prominent nodes to 60 mm distant; foraging shoot compressed-rectangular in cross section, to 3 mm diam., with a few oblong cataphylls and reduced foliage-leaves at first but soon becoming naked with slightly prominent nodes to 120 mm distant. Leaves when fresh grey- to dark green, paler abaxially, air drying dull greenish brown; petiole 2 – 70 x 2 – 20 mm, broadly winged, obovate-oblong to linear-oblong or elongate-triangular, with 2 – 3 secondary veins and numerous veinlets per side, all veins prominent, especially in dried material, base decurrent to clawed, apex truncate to prominently auriculate; lamina 25 – 140 x 15 – 50 mm ovate to elliptic or lanceolate with (1 –) 2 – 3 intramarginal veins per side, these arising from the base and either immediately diverging, reaching the leaf tip or merging into distally into a prominent submarginal collecting vein, additional veins arising obliquely from the midrib, remaining parallel with numerous veins arising from them, base broadly rounded to acute, apex ovate to attenuate-mucronate, acute or attenuate, minutely tubulate. Flowering shoot arising from the mid- to distal leaf axils of fertile shoots, bearing a minute prophyll and several 3 – 30 mm sequentially longer cataphylls. Inflorescence solitary; peduncle 30 – 100 x c. 2 mm, rather stout, erect, curving to bring the inflorescence upright in shoots pendent under their own weight, pale yellow; spathe 10 – 35 x 5 – 10 mm, ovate to reniform, concave, spreading to reflexed, base cordate, clasping and briefly decurrent on the peduncle, apex fornicate, obtuse with a prominent mucro, yellowish to greenish white; spadix stipitate; stipe 5 – 40 x 1 – 2 mm, terete in cross section, expanded distally, erect, straight, greenish yellow-white; fertile portion 10 – 13 x 10 – 15 mm, globose-clavate to ovoid, minutely clasping where inserted on the stipe, mid-yellow. Flowers 1 – 2 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform, mid-yellow, apex fornicate, truncate; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae globose, c. 0.2 mm diam., pale yellow; ovary 1 – 1.5 x 0.25 – 0.75 mm, compressed angular-ellipsoid, yellow-green; stylar region truncate, yellow; stigma punctiform. Infructescence with few to numerous berries; fruit obclavate to ovoid or ellipsoid, 10 – 1705 x 10 – 20 mm, scarlet. Seeds c. 3 – 6 mm diam., ellipsoid to compressed-globose.
Distribution — Cambodia(?),Vietnam.
Habitat & Ecology — Damp evergreen forest on granite outcrops in otherwise anthropegenic grassland and agricultural land, variously degraded forest on sandstone and granite. 95 – 650 m.
Notes — The most spectacular Pothos in Indochina, forming extensive colonies distinctive by the large grey-green leaves and long flowering shoots pendent under the weight of numerous large waxy yellow-and-white slightly fragrant inflorescences. The juvenile stage is equally striking with compressed, winged, rectangular stems densely clothed with blue- to grey-green leaves closely appressed to boulders and tree trunks.
Together with P. grandis and P. macrocephalus, the smaller-inflorescenced P. pilulifer and P. kerrii and some Malesian species (e.g. Javan P. junghuhnii), P. gigantipes is typical of this species assemblage defined by inflorescences with mostly long peduncles, long stipes and globose to ovoid or cylindrical spadicies.
Pothos gigantipes appears to be rare. Boyce 1195 and Nguyen Van Dzu 173, collected contemporaneously from different individuals, were the first gatherings for over fifty years and together brought the number of known Vietnamese collections of P. gigantipes to five. A large flowering individual was observed but not collected in Khanh Hoa, Khan Son district, Vietnam in 1998 (Boyce & Dzu, pers. obs.)
The Cambodian record cited here is based on a sterile collection of three juvenile adherent shoots that, while closely resembling Vietnamese collections, is impossible to place with certainty.

Geographically representative selection of collections studied:
CAMBODIA. Locality not given: Collard s.n., (P).
VIETNAM. Khanh Hoa: Khanh Vinh, Khanh nam, 17 March 1997, Boyce 1195 (fl., fr.) (HN, K and K Spirit Coll. no. 63298, M). Quang Nam – Da Nang: Ba Na, near Danang, 015° 59’N, 107° 59’E, 11 July 1923, Poilane 7062 (fl.) (P). Thua Thien Hue: Thua Luu F.D., 016°’ 18N, 108° 00’E, 16 May 1918, Chevalier 37045 (fl., fr.) (type of Pothos gigantipes P holo).