Pothos Grandis Buchet

4. Pothos grandis Buchet ex P.C. Boyce & D.V. Nguyen — Figs 4, 4a.

Pothos grandis Buchet apud Gagnep. ex P.C. Boyce & D.V. Nguyen, Kew Bull. 50(4) (1995) 754; P.H. HÈ, CâaycÀ Vi_tnam [Ill. Fl. Vietnam – in Vietnamese & English], 3(1) (1993) 421, pl.8255— [P. grandis Buchet apud Gagnep. in Lecomte, Fl. Gén. l’Indo-Chine 6 (1942) 1088, nom.invalid., sine descr. Latin.] — Type: Vietnam, Hoa Binh, Kim Boi, June 1926, Colani 3002 (P! holo; P!, SAI! iso).

Moderate-sized, rather robust homeophyllous root-climbing liane and hammock-forming secondary hemiepiphyte 3 m. Eocaul not observed; stem of juvenile shoot to 4 mm diam., sharply four-angled, minutely winged along the angles, leaves rather scattered; stem of mature sterile shoot to 8 mm diam., deep green, becoming black-brown with age, drying dark green to almost black, weakly four-angled or slightly compressed-terete in cross section, at first somewhat sparsely clothed with leaves, later naked, naked portions with prominent, slightly stepped nodes to 50 mm distant, stem of fertile shoot to 4 mm diam., mostly moderately clothed with leaves, occasionally older portions naked for approximately half their length, naked portions with prominent, stepped nodes to 30 mm distant; foraging shoot to 2 mm diam. with a few cataphylls and reduced foliage-leaves at first but soon becoming naked with slightly prominent nodes to 100 mm distant. Leaves when fresh deep green adaxially, paler and slightly yellowish abaxially, drying dull olive green; petiole 20 – 50 x 10 – 20 mm, broadly winged, obovate-oblong, with 2 – 3 secondary veins and numerous veinlets per side, all veins prominent, especially in dried material, base decurrent, apex truncate to rounded or slightly auriculate; lamina 140 – 230 x 55 – 100 mm, ovate with 2 intramarginal veins per side, these arising from the base and either reaching the leaf tip or merging into a prominent submarginal collecting vein, all additional veins arising obliquely from the midrib, remaining parallel with numerous veins arising from them, base rounded, apex acuminate-mucronate. Flowering shoot much abbreviated, arising from the middle and distal leaf axils of fertile shoots, bearing a minute prophyll and up to seven 4 – 30 mm, sequentially longer, cataphylls. Inflorescence solitary; peduncle 40 – 70 x 2 – 3 mm, robust, erect, tapering towards the apex, deep purple; spathe 25 – 52 x 20 – 30 mm, ovate to ovate-lanceolate, margins prominently inrolled, base slightly cordate to decurrent, apex acute with a somewhat stout mucro, deep purple, sometimes slightly greenish abaxially when fresh, drying almost black; spadix stipitate; stipe 12 – 15 x c. 2 mm, terete in cross section, deep purple; fertile portion 12 – 30 x 9 – 13 mm, ovoid to clavate, yellow-green to off-white. Flowers c. 2 – 3mm diam.; tepals 6, 4 x 1.3 mm, oblong-cymbiform, yellow-green to dirty white, apex fornicate, triangular, truncate; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae 1 x 0.25 mm cream; ovary 5 x 1.75 mm, 3-locular, compressed angular-ellipsoid, yellow-green to dirty white; stylar region truncate; stigma prominent, punctiform, purple. Infructescence with 4 – 10 berries; fruit obclavate, 10 – 17.5 x 10 – 14 mm, green ripening through yellow to deep orange-red. Seeds c. 5 – 8 mm diam., ellipsoid to compressed-globose.
Distribution — Vietnam.
Habitat & Ecology — On trees and cliffs in fragments of very degraded lowland to lower hill evergreen forest on Karst limestone formations. 75 – 250 m.
Vernacular name — Co´m lênh la´buo´i (Vietnamese).
Notes — The large sombre-coloured inflorescence, although less eye-catching than, for example, P. gigantipes, makes for a striking plant. Similar overall to P. dzui but differing by the ovoid to clavate spadix and by the spreading to slightly reflexed spathe.
To date P. grandis has only been recorded from Vietnam. However, the he collection from Pac Mo, Lang Son province (Soviet-Vietnam Expedition 1137) was made close to the border with China and P. grandis is to be expected in southern China.

Geographically representative selection of collections studied:
VIETNAM. Hanoi: Dong Ham, near Kien Khe, 14 May 1883 (fl.), Bon 2152a,b (fl.) (P). Ha Tay: My Duc, Chua Huong, 28 May 1977, Nguyen Thi Nhan HN 111 (fl.) (HN). Hoa Binh: Kim Boi, June 1926, Colani 3002 (fl.) (type of Pothos grandis, P holo; P, SAI iso). Kon Tum: Dak Glai, 29 March 1978, Tran Ding Ly 389 (fl.) (HN). Lang Son: Pac Mo, 23 March 1961, Soviet-Vietnam Expedition 1137 (fl.) (LE). Nghe An: From Phu Qui to Kebon, Poilane 16565 (fl.) (P, SAI). Ninh Binh: Cuc Phuong Nat. Park, 6 Jan. 1963, Nguyen Quo Chung HN 2130 (fl.) (HN).