7. Pothos pilulifer Buchet ex P.C. Boyce, sp. nov.
[P. pilulifer Buchet apud Gagnep. in Lecomte, Fl. Gén. l’Indo-Chine 6 (1942) 1084, nom. invalid. sine descr. Latin.; P.H. HÈ, Cây-cÀ Miê__ Nam Vi_t-nam [Fl. South Vietnam – in Vietnamese] (1960) 690, pl.267, E; C.Y. Wu & H. Li, in C.Y. Wu & H. Li, Fl. Yunnan., 2 (1979) 742; H. Li in C.Y. Wu & H. Li, Fl. Reip. Pop. Sinicae 13(2) (1979) 18; J. Zhong, Ill. Limestone Mount. Pl. Guangxi (1982) 292; P.H. HÈ, CâaycÀ Vi_tnam [Ill. Fl. Vietnam – in Vietnamese & English], 3(1) (1993) 422, pl.8257]

Pothos pilulifer cum P. kerrii confundatur, sed inflorescentia paene sessili, stipite longo recto crasso atque spadice fertili globoso parvo facile agnoscitur — Typus: Vietnam, Lang Son, Dong Dang, 021° 57’N, 106° 42’E, Feb. 1886, Balansa 261 (fl.) (P! holo, K! iso),

Moderate to large, robust homeophyllous root-climbing liane to 5 m. Eocaul not observed; stem of juvenile shoot to 4 mm diam., rectangular in cross section, angles slightly winged, leaves congested; stem of mature sterile shoot to 12 mm diam., rectangular in cross section, more-or-less compressed, the angles minutely but prominently winged, stems at first somewhat densely clothed with leaves, eventually becoming naked, naked portions with prominent 70 mm distant nodes; fertile shoot often not branching, stem to 3 mm diam., somewhat prominently angled in cross section, the angles minutely winged, leaves somewhat distant, older portions retaining their leaves in specimens observed. Leaves leaves when fresh mid-green adaxially, paler abaxially, air drying brownish green; petiole 10 – 40 x 4 – 17 mm, somewhat narrowly to rather broadly winged, obovate-oblong to linear-oblong or elongate-triangular, with 2 – 4 secondary veins and numerous veinlets per side, all veins, but particularly secondary veins, prominent, especially in dried material; lamina 35 – 110 x 20 – 50 mm, ovate to elliptic or lanceolate with 2 – 4 intramarginal veins per side, these arising from the base and either immediately diverging or remaining very close and parallel to midrib and then diverging further along lamina, either reaching the leaf tip or merging into a prominent submarginal collecting vein, additional veins arising obliquely from the midrib, remaining parallel with numerous veins arising from them, base decurrent, apex truncate, rounded or auriculate, base rounded to subacute, apex attenuate, somewhat prominently tubulate. Flowering shoot much abbreviated, arising mostly from of the upper-middle to distal leaf axils of fertile shoots, bearing a minute prophyll and a few 3 – 8 mm, sequentially longer, cataphylls. Inflorescence solitary; peduncle 0 – 3 (– 5) x c. 1 mm, stout, erect, green; spathe 4 – 5 x 2.5 – 4 mm, ovate, concave, margins strongly inrolled, base decurrent on the peduncle, apex fornicate to recurved, acute, green to greenish purple; spadix stipitate; stipe 10 – 12 x 1 – 1.25 mm, terete, erect, straight to slightly curved, stout, green to greenish purple; fertile portion 4 – 5 x 4 – 5 mm, globose, yellow. Flowers c. 1 – 2 mm diam.; tepals 0.5 x 0.3 mm, oblong-cymbiform, apex fornicate, triangular, truncate; stamens 1 – 1.1 x c. 0.5 mm, filaments strap-shaped, thecae c. 0.2 mm diam., yellow; ovary 1 – 1.5 x 0.25 – 0.75 mm, compressed angular-ellipsoid, yellow-green to dirty white; stylar region truncate; stigma punctiform. Infructescence not observed.

Distribution — China (Guangxi), Vietnam.

Habitat & Ecology — Seasonal to moist evergreen forest on limestone rocks. 300m.

NotePothos pilulifer is superficially similar to P. kerrii, differing by broader leaves and an inflorescence with a very short, stout pedicel, a stout, straight stipe and a slightly larger fertile spadix.
There are only seven recorded collections of P. pilulifer, all but two originating from northern Vietnam. Unlike the situation with P. kerrii (q.v.) the paucity of collections seems to reflect natural rarity; P. pilulifer is seldom encountered in nature.

Geographically representative selection of collections studied:
CHINA. Guangxi: Longjing, 18 Dec. 1958, Zhang Zhaoqian 12744 (fl.) (MO).
VIETNAM. Ha Tay: Huong Son, Phu Ma, 26 May 1977, Ha Thin Dung 197 (fl.) (HN). Lang Son: Dong Dang, 021° 57’N, 106° 42’E, Feb. 1886, Balansa 261 (fl.) (type of Pothos pilulifer, P holo, K iso). Lao Cai. Phong Tho, 022° 32’N, 103° 21’E, 6 Dec. 1937, Poilane 26730 (fl.) (P). Ninh Binh. Cuc Phuong, 25 Oct. 1995, Nguyen Van Dzu 79 (fl.) (HN).