8. Pothos repens (Lour.) Druce

Pothos repens (Lour.) Druce, Rept. Bot. Exch. Club Brit. Isles, 4 (1916) 641; Gagnep. in Lecomte, Fl. Gén.l’Indo-Chine, 6 (1942) 1088 – 1089; P.H. HÈ, Cây-cÀ Miê__ Nam Vi_t-nam [Fl. South Vietnam – in Vietnamese] (1960) 690, pl.267, B; Fl. Hainan., 4 (1977) 130 – 131, pl.1034; C.Y. Wu & H. Li, in C.Y. Wu & H. Li, Fl. Yunnan., 2 (1979) 744, pl.202, 9; H. Li in C.Y. Wu & H. Li, Fl. Reip. Pop. Sinicae 13(2) (1979) 20 – 21, pl.3, 9; M.L. Sai in Y.K. Li et al., Fl. Guizhou., 6 (1987) 548 – 549, pl.161, 2; P.H. HÈ, CâaycÀ Vi_tnam [Ill. Fl. Vietnam – in Vietnamese &English], 3(1) (1993) 420 – 423, pl.8258. — Flagellaria repens Lour., Fl. Cochin., 1 (1790) 212. — [Pothos loureiroi Hook. & Arn. in Beechey, Voy. (1841) 220, nom. illeg., Flagellaria repens pro. syn. incl. type.] — [Pothos repens (Lour.) Merr., Philipp. J. Sci. 15 (1919) 228, comb. superfl.]. — Neotype desginated here: Vietnam, Quang Nam-Da Nang, Ba Na hillstation, base of mountain at start of trail to summit, c. 24 km SW of Danang, 16° 01’N, 108° 01’E, 13 March1997, Boyce 1188 (fl.) (HN!, K! and K Spirit Coll. no. 63299!, M!). Despite exhaustive enquiries and searches in G, P & BM I have failed to trace a type specimen for the name Flagellaria repens Lour. In proposing the name Flagellaria repens Loureiro cites the plate of Adpendix duplo folia [Rumphius, Herb. Amb. 5 (1747) pl.184, f.1]. Geographical considerations aside ( P. repens is restricted to southern China and northern Indochina) Rumphius’s illustration is too crude to be identifiable to species. Loureiro’s description and geographical data agree unmistakably with the common Pothos in northern Indochina here taken to be P. repens.Pothos terminalis Hance, Ann. Sc. Nat. Bot., 5, sér. 5 (1866) 247. — Type: China, Guangdong, Ting Wu Shan, West River, Sampson 11168, June 1864 (BM! holo, GH!, K! iso) [Pothos hainanensis S.Y. Hu, nom. nud. in sched. C, GH, K et MO]

Moderate to very large, slender to robust, homeophyllous root-climbing liane to 15 m. Eocaul foraging and weakly climbing, apparently of indeterminate length but apparently often (perhaps always) terminating through meristematic damage and reiterating from one or more lateral buds, leaves congested, subshingling but not different in shape to those of adult shoots; stem of juvenile shoot to 4 mm diam., weakly angled or terete in cross section, leaves initially subshingling, later merely congested; stem of mature sterile shoot to 20 mm diam., mid-green, becoming greyish with age, drying yellowish brown, weakly four-angled or slightly compressed-terete in cross section, often somewhat sinuous, densely clothed with leaves, later becoming naked, naked portions with prominent nodes to 60 mm distant; reiteration shoot exceptionally robust, to 20 mm diam., rooting prolifically, leaves densely imbricated and directed upwards, later spreading. Leaves when fresh bright to deep-green adaxially, paler abaxially, air drying yellowish to brown; petiole 50 – 200 x 5 – 25 mm, broadly winged, oblong-obovate-lanceolate to linear-oblong, with 2 – 3 barely differentiated primary veins running parallel to midrib and numerous parallel to subparallel and reticulate veinlets per side, primary and larger secondary veins reaching the petiole tip and there curving inwards to merge with the leaf lamina/petiole junction, veins not especially prominent, base decurrent, apex truncate, slightly auriculate; lamina 20 – 80 x 10 – 20 mm (lowermost leaves on a shoot sometimes only with a vestigial lamina), ovate to elliptic or triangular-lanceolate, with 3( – 5) more-or-less parallel primary veins arising from the base reaching the lamina tip, base rounded to truncate, apex subacute to acute, briefly tubular-mucronate; fertile shoot branching to three or more orders, often pendent to great length, stem to 5 mm diam., densely clothed with leaves, older portions naked for approximately half their length, naked portions with prominent, stepped nodes to 30 mm distant; flowering shoots somewhat abbreviated to well-developed by enrichment, arising from few to several of the distal leaf axils of fertile shoots, occasionally arising from naked older portions of shoot, bearing a minute prophyll and a few to many 5 – 40 mm, sequentially longer, cataphylls, the longest sometimes furnished with a prominent vestigial leaf lamina. Inflorescences solitary to several together, either congested or spaced along a leafy to naked branching system to 20 mm long; peduncle 3 – 8 x 0.5 – 2 mm, slender, curving to spreading, terminal portion erect, green; spathe 20 – 70 x 3 – 6 mm, elongate-elliptic, strongly reflexed and occasionally bent at anthesis, margins recurved to reflexed, base briefly decurrent, apex apiculate to shortly filiform, greenish, margins stained purple; spadix stipitate; stipe 10 – 130 x 1 – 1.2 mm, terete in cross section, erect, greenish to purple; fertile portion 40 – 80 x 2 – 4 mm, slender cylindrical, sometimes strongly obliquely inserted on stipe, yellow-green to off-white. Flowers c. 1 – 2 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform, apex fornicate, triangular, truncate; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae c. 0.2 mm diam.; ovary 1.6 x 0.25 mm, compressed angular-ellipsoid, greenish to whitish; stylar region truncate; stigma prominent, punctiform. Infructescence with few berries; fruit 7 – 15 x 10 – 14 mm, turbiniform to ellipsoidal, globose at maturity. Seeds c. 3 – 6 mm diam., ellipsoid to compressed-globose.

Distribution — China (Guangdong, Guangxi, Hainan, Hong Kong), Lao P.D.R., Vietnam.

Habitat & Ecology — Primary to heavily disturbed evergreen hill forest, dry secondary forest with bamboo, woodland, thickets and scrub, open, damp Pinus kaempferi plantation, occasionally on bare rocks or limestone formations, usually on sandy soil or limestone on moderate to steep slopes, 85 – 1000 m.

Notes — A large, occasionally exceptionally so, distinctive climber with long pendent fertile shoots carrying distichous leaves composed of an expanded and greatly elongated petiole and an often semi-vestigial lamina. The inflorescences are comparatively large and slender, arising from the uppermost leaves of a shoot, and having the appearance of fascicles of inflorescences. Although very distinctive when flowering, sterile specimens of P. repens can be confused with P. scandens and vice versa. Confusion can also occur between P. repens and the vegetatively similar Pothoidium lobbianum Schott. The latter is a predominantly Malesian monotypic genus recorded from southern Taiwan but not recorded for mainland Asia.

Geographically representative selection of collections studied:
CHINA. Guangdong: Ting Wu Shan, West River, June 1867, Sampson 11168 (fl.) (BM, GH, K). Guangxi: Lungchow, 'Lung Yiock', Dec., Morse 203 (fl.) (K). Hainan: Ngai, between T'ang K'iu (Din-Kio) and Po T'eng Shi (BoDeng), 23April – 23 May 1932, McClure 20053 (fl.) (BM, E, GH, K, MO, P). Hong Kong: Aberdeen, Lamont s.n. (fl.) (L).
LAO P.D.R. Savannakhet: Ban Phonthan, 015° 41’N, 106° 28’E, Spire 212 (fl.) (P).
VIETNAM. Gia Lai: K'bang district, Buon Luoi, c. 40 km NW of An Khe, 14 March 1997, Boyce 1193 (fl.) (HN, K, M). Ha Tay: Ba Tai valley, foot of Ba Vi, 022° 27’N, 105° 01’E, 12 April 1888, Balansa 2063 (fl.) (K, P). Hai Phong: Chau Mong, 020° 44’N, 106° 33’E, 17 – 18 April 1914, Fleury 32163 (fl.) (K, P). Hoa Binh: Tan Lac, Man Duc, 020° 36’N, 105° 18’E, 30 Aug. 1994, Boyce 863 (fl.) (HN, K). Lang Son: Noi Tiem, 022° 28’N, 106° 11’E, 26 April 1961, Soviet-Vietnam Expedition 1382 (fl.) (LE). Ninh Binh: Cuc Phuong N.P., Doan Khao Sat Viet Trung 4904 (fl.) (HN). Quang Nam-Da Nang: Ba Na hillstation, base of mountain at start of trail to summit, c. 24 km SW of Danang, 16° 01’N, 108° 01’E, 13 March 1997, Boyce 1188 (fl.) (neotype of Pothos repens, HN, K and K Spirit Coll. no. 63299, M); Da Nang, 3 June 1920 (fr.)
Poilane 1465. Quang Ninh: Sai Vong Mo Leng, Lung Wan, 021° 26’N, 107° 32’E, 18 May – 5 July 1940, W.T. Tsang 29998 (fl.) (BKF, C, GH, K, P). Quang Tri: Quang Tri, 016° 45’N, 107° 15’E, 4 June 1924, Poilane 10770 (fl., fr.) (P). Than Hoa: Near Quang Yen, 019° 33’N, 105° 31’E, Aug. 1885, Balansa 615 (fl.) (K, P). Thua Thien Hue: Phu Loc, 43 km SE of Hue on Highway 1, 11 March 1997, Boyce 1183 (fl.) (HN, K and K Spirit Coll. no. 63297, M). Tuyen Quang: Long Tcheoung, Simond s.n. (fl.) (P, SAI). Vinh Phu: Tam Dao, c. 100 km NW of Hanoi, 21° 27’N, 105° 38’E, 6 March 1997, Boyce 1159 (fl.) (HN, K, M). Yen Bai: 'Dep Tam', 5 May 1961, Soviet-Vietnam Expedition 1851 (fl.) (LE).