1. Pothos chinensis (Raf.) Merr.

Pothos chinensis (Raf.) Merr., J. Arn. Arb. 24 (1948) 210; Benth., Fl. Hongkong. (1841) 345 (as P. scandens); F.C. How, Fl. Kwangchow (Canton) [= Guangzhou] (1956) 693 – 694; Fl. Hainan., 4 (1977) 130; C.Y. Wu & H. Li, in C.Y. Wu & H. Li, Fl. Yunnan., 2 (1979) 742 – 744, pl.208, 8; H. Li in C.Y. Wu & H. Li, Fl. Reip. Pop. Sinicae 13(2) (1979) 19 – 20, pl.3, 10; M.L. Sai in Y.K. Li et al., Fl. Guizhou., 6 (1987) 546 – 548, pl.161, 1 — Tapanava chinensis Raf., Fl. Tellur. 4 (1837) 14 (1837). — Type: Bot. Reg. 16 (1830) pl.1337. Pothos seemanni Schott, Bonplandia 5 (1857) 45. — Neotype designated here: China, Hong Kong, Champion s.n. (K!). In describing P. seemanni Schott did not explicitly cite any specimens although later (Schott 1860) cited material from Seemann’s Herbarium without specifying collector or number. Typification of Schott names for which no specimens are extant on illustrations in the Icones Aroideae is often practiced but I prefer to follow Grayum (1996: 4 – 5) in utilizing Icones Aroideae illustrations as a means to identify herbarium specimens seen by Schott. Among the Icones Aroideae there is a plate of P. seemanni [Icones Aroideae 2869 (W!); Schott 1983] on which the short robust flowering branch, fruiting spadix and inflorescence cataphyll details depicted are a perfect match for the Kew Champion specimen cited above. The long slender flowering branch depicted in the same Icones is yet to be traced to a specimen. Pothos cathcartii Schott, Aroid. (1858) 22 (as ‘cathcarti’), syn. nov. — Type: India, Sikkim, April 1850, Cathcart s.n. sub. Hooker s.n. (fl.) (K! holo) Pothos warburgii Engl., Bot. Jahrb. Syst. 25 (1898) 2, syn. nov. — Type: Taiwan, Kuanania, Warburg 10663 (B† holo, BM† iso; see note below) Pothos balansae Engl., Bot. Jahrb. Syst. 25 (1898) 3, syn. nov. — Type: Vietnam, Mt. Bavi, Lankok valley, Balansa 2060 (P! holo, K! iso) Pothos yunnanensis Engl. in Engl., Pflanzenr. 21(IV.23B) (1905) 28 — Type: China, Yunnan, Szemao, Henry 11779 (B† holo, E!, GH!, K! iso) Pothos chinensis (Raf.) Merr. var. lotienensis C.Y. Wu & H. Li, Acta Phytotax. Sin., 15(2) (1977) 101, syn. nov. — Type: China, Guizhou, Luodiang, Qian-nan Team 731 (KUN! holo) [Pothos yunnanesis Engl. var. bonii Buchet, nom. nud. in sched. P]

Small to very large, slender to robust homeophyllous root-climbing liane to 10 m. Eocaul not observed; stem of juvenile shoot to 4 mm diam., weakly angled or terete in cross section, leaves congested; stem of mature sterile shoot to 12 mm diam., weakly four-angled, slightly compressed or terete in cross section, mid-green, becoming greyish brown with age, at first somewhat densely clothed with leaves, early growth often with all leaves directed forwards and the whole appearing imbricated, later growth with leaves spreading, stems eventually becoming naked, naked portions with prominent, 70 mm distant nodes; fertile shoot often branching to three or more orders, stem to 5 mm diam., terete to weakly or somewhat prominently angled in cross section, angles occasionally minutely winged, mostly densely clothed with leaves, older portions naked at the base to approximately half their length, naked portions with prominent nodes to 30 mm distant; foraging shoot subterete in cross section, to 2 mm diam., proximally with a few oblong cataphylls and reduced foliage-leaves but soon becoming naked with slightly prominent nodes to 150 mm distant. Leaves when fresh bright to mid-green adaxially, paler abaxially, air drying dull green to brownish; petiole 0.5 – 140 mm x 4 – 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, rounded or auriculate; lamina 30 – 205 x 15 – 205 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 rounded to acute, apex attenuate-mucronate to acute or attenuate, minutely tubulate. Flowering shoot much abbreviated, arising from most of the mid- to distal leaf axils of fertile shoots, bearing a minute prophyll and a few 3 – 15 mm sequentially longer cataphylls. Inflorescence solitary; peduncle 3 – 25 x 1.5 – 2.5 mm, rather stout, erect to variously curved, green to brown-tinged; spathe 4 – 12 x 4 – 10 mm, ovate, concave, margins inrolled, base cordate, clasping and slightly decurrent on the peduncle, apex fornicate to recurved, acute to subacute with a rather stout mucro, greenish white to green, occasionally faintly purple-tinged, somewhat waxy; spadix stipitate; stipe 5 – 10 x 1 – 1.25 mm, terete in cross section, erect, straight, green; fertile portion 3.5 – 13 x 3 – 10 mm, globose to ovoid, pale green to white. Flowers c. 1 – 2 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform, yellow-green to dirty white, apex fornicate, triangular, truncate; stamens 1 – 4 x c. 0.5 mm, filaments strap-shaped, thecae 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 with 1 – 5 berries; fruit 10 – 17.5 x 10 – 14 mm, obclavate to ovoid or ellipsoid, mid-green ripening to scarlet, often with basal chartaceous tepal remains. Seeds c. 3 – 6 mm diam., ellipsoid to compressed-globose.

Distribution — Bangladesh, Bhutan, Cambodia, China (Guangdong, Guangxi, Guizhou, Hainan, Hong Kong, Hubei, Macao, Sichuan, Yunnan), India (Arunchal Pradesh, Assam, Manipur, Nagaland, Orissa, Sikkim, Tripura, West Bengal), Lao P.D.R., Myanmar, Nepal, Taiwan, Thailand, Vietnam.

Habitat & Ecology — On rocks and trees and in clearings in tropical or subtropical primary or disturbed lowland wet or dry evergreen forest, rainforest, hill evergreen forest, wet upper hill to lower montane forest, ravines, in dry thickets and orange orchards, sometimes in association with tall grasses and bamboo on sandstone, limestone, granite, clay, loam or sandy soil. 250 – 2970 m.
Vernacular names — Cag kheb (Thailand: Chiang Mai), Tun wa (Thailand: Chiang Mai), Hmab Ntsua Nees (Thailand: Nan, Hmong dialect), Wai Ta-kep (Thailand: Chiang Mai).

Ethnobotany — Thailand: used fresh and applied topically on insect and animal bites [Brun et al. 502 (C)]; entire plant as a decoction in bath to treat tumours [Brun et al. 704 (C)]; plant boiled and the liquid drunk for cough [Anderson 5572 (GH)].

Notes — The differences cited by Engler (1905) & Gagnepain (1942) between P. chinensis, P. yunnanensis, P. balansae and P. cathcartii concern the shape and dimensions of the fertile portion of the spadix. Study of numerous herbarium specimens and of living plants in the field demonstrates that these distinctions are unreliable.
The name P. chinensis has been applied to slender climbers with a short petiole (less than one third as long as leaf lamina) and small inflorescences with a prominent stipitate spadix. Many of the collections agreeing with P. chinensis s.s. (i.e. sensu Engler 1905) are from Hong Kong and Taiwan. However, numerous collections from mainland China and further afield blur these differences and, occasionally, different duplicates of the same collection have been identified as separate species depending on their robustness.
Pothos cathcartii is dimensionally in the mid-range of the complex with generally medium sized inflorescences, and leaves with the petiole and lamina approximately equal in length. However, the isotype of P. cathcartii in K has a branch with individual inflorescence dimensions matching both P. yunnanensis and P. cathcartii.
The names P. yunnanensis Engl. and P. balansae Engl. have been applied to robust specimens. The isotype of P. yunnanensis at K is an exceptionally robust specimen with leaf laminae in excess of 200 mm long and several stout inflorescences each carried on a 20 mm long peduncle. However, the isotype in GH is decidedly smaller in stature and bears inflorescences whose dimensions fit well P. cathcartii s.s. Engler (1905) distinguished P. balansae by the oblong fertile portion of the spadix. The types of P. balansae in P and K are in young fruit, the spadices distorted by the enlarging ovaries. During fieldwork on Ba Vi (the type locality of P. balansae) in 1994 and 1997 I observed plants on which, depending on the age of the inflorescences, different branches could be matched to ‘typical’ P. chinensis or P. cathcartii or P. balansae. There is a continuum between the four species as defined by Engler and none can be satisfactorily separated from another. The oldest name, P. chinensis, is therefore adopted.
Pothos warburgii Engl., described from Taiwan, also belongs here. The holotype at B is missing, presumed destroyed. The isotype at the BM is also missing, with only the torn labels remaining in a capsule mounted on Warburg 9697. Based on Engler’s protologue and illustration (presumably based on the missing holotype since Engler cites no other specimen) P. warburgii is a slender-leaved form of P. chinensis.
Confusion can occur between P. scandens and P. chinensis. In flower P. chinensis is immediately recognizable by the straight, not bent, stipe and the generally larger, paler, fewer, more scattered inflorescences. Generally P. scandens has flowering shoots arising at many of the leaf axils of long pendent fertile shoots, thus there are often numerous inflorescences. By contrast P. chinensis tends to produce flowering shoots at only the distal-most leaf axils of short spreading fertile shoots, thus inflorescences are rather few. Inflorescence colours also differ; purple spathe and cream fertile spadix in P. scandens, green spathe and white to yellow fertile spadix in P. chinensis.
Sterile material of P. chinensis can be difficult to differentiate from P. scandens. Generally the petioles are less than half as long as the lamina, and the lamina is twice or more as broad as the petiole, narrower and with a attenuate apex. However, variation is such that intermediates are common. A feature noted in P. chinensis, but yet to be recorded for P. scandens, is the occurrence of flagelliform foraging shoots.

Geographically representative selection of collections studied:
CHINA. Guangdong: Ting Wu Shan, 7 May 1928, W.Y. Chun 6458 (fl.) (GH). Guangxi: Loh Hoh Tsuen, Ling Yun Hsien, 1933, Steward & H.C. Cheo 62 (fl.) (GH, P). Guizhou: Esquirol 70 (K). Hong Kong: New Territories, Tai Mo Shan, 10 Oct. 1969, S.Y. Hu 8121 (fl.) (GH, K). Hubei: Ichang, Nan-to mountains, May 1888, Henry 4395 (fl.) (GH, K). Hainan: Bo Ting, 21 Oct. 1936, S.K. Lau 28069 (fl.) (GH). Macao: 1844, Callery 195 (K, P). Sichuan: Omei Shan, 8 Aug. 1938, C.Y. Chiao & C.S. Fan 254 (fl.) (GH). Yunnan: Meng-soong, Dah-meng-lung, Che-li Hsien, Sept. 1936, C.W. Wang 78408 (fl.) (GH).
LAO P.D.R. Khammouan: Phou Phoung, 2 March 1932, Poilane 20278 (fl.) (P). Louangphrabang: Phou Ngoi, near Louangphrabang, 2 April 1932, Poilane 20612 (fl.) (P). Xieng Khouang: Between La Mine and Nadin, April 1949, Vidal 917 (fl.) (SAI).
MYANMAR. Kachin: Sumprabum, eastern approaches from Sumprabum to Kumon range, between Mache Ga and Sumprabum, 026° 40’N, 097° 20’E, 23 Jan. 1962, Keenan et al. 3381 (fl.) (GH, K). Sagaing: Katha, Kadu Hill, 23 Feb. 1916, Lace 5112 (fl.) (K).
TAIWAN. Nantou Hsien, Chitou, San-cha-lun, 17 Feb. 1960, T.I. Chuang & M.T. Kao 3259 (fl.) (GH).
THAILAND. N2. Chiang Mai: Doi Inthanon, trail just past check point 2, km32 on road to summit, 20 Sept. 1994, Boyce 983 (fl.) (BKF, K and K Spirit Coll. no. 59590). N5. Nan: Doi Phukha N.P., by roadside to summit, 019° 10’N, 100° 06’E, 22 Sept. 1996, Boyce 1124 (fl.) (BKF, K, TCD). N8. Phrae: Mae Khaem, 018° 07’N, 100° 09’E, 2 Jan. 1972, Beusekom et al. 4659 (fl.) (BKF, C, K, L). N10. Tak: Doi Pae Poe, about 90 km NW of Tak, 14 March 1968, Hansen & Smitinand 12909 (fl.) (BKF, C). N12. Phitsanulok: So Pah, waterfall west of Tung Salaeng Luang, 22 July 1966, Larsen et al. 713 (fl.) (BKF). NE16. Petchabun: Nam Nao N.P., trail west from visitor centre, 23 Sept. 1994, Boyce 1012 (fl.) (BKF, K). NE17. Loei: Dong Phrab Pran, Phu Rua N.P., 017° 28’N, 101° 18’E, 5 March 1993, Chantaranothai et al. 1087 (fl.) (BKF, K, KKU, TCD. E28. Nakhon Ratchasima: Khao Yai NP, near old forest station, 14 March 1968, Beusekom & Phengklai 51 (fl.) (BKF). SW37. Kanchanaburi: Sai Yok, 18 Dec. 1961, Larsen 8810 (fl.) (GH). C47. Saraburi: Kaeng Khoi, Than Pra Photisat, 7 Oct. 1979, Shimizu et al. 19394 (fl.) (BKF). SE57. Prachin Buri: Ban Bung hills, 2 Aug. 1966, Larsen et al. 1137 (fl.) (AAU, BKF, GH). SE61. Chantaburi: Kao Satap, 7 Jan. 1930, Kerr 17999 (fl., fr.) (BK, K, L, P). PEN66. Phangnga: Kao Bangto, 22 Feb. 1929, Kerr 17187 (fl.) (BK, K, P).
VIETNAM. Cao Bang: Tra Linh, Quoc Toan, near Thang Heng lake in environs of Thang Heng and Lung Tao villages, 4 Jan. 1996, Averyanov et al. VH 2472 (fl.) (HN). Ha Tay: Bavi, Lan Kok valley, 022° 27’N, 105° 01’E, 16 April 1888, Balansa 2060 (fl.) (type of Pothos balansae Engl. P holo; K iso). Khanh Hoa: Lung Van, 26 Jan. 1931 (fl.) Poilane 18922 (P). Kon Tum: Dak Glai, 26 March 1968, Nguyen Kim Dao 161 (fl.) (HN). Lai Chau: Dien Bien Phu, Muong Fang, 3 June 1961, Soviet-Vietnam Expedition 2427 (fl.) (LE). Lang Song: Van Linh, Feb. 1938, Pételot 2286 (fl.) (GH, SAI). Nghe An: Quy Chan, 25 Aug. 1963, Trinh Xuan Mai 737 (fl.) (HN). Ninh Binh: Cuc Phuong N.P., c.100 km SW of Hanoi, 20° 16’N, 105° 40’E, 7 March 1997, Boyce 1164 (fl.) (HN, K and K Spirit Coll. no. 63241.005, M). Quang Nam – Da Nang: Ba Ma, near Da Nang, 2 March 1939, Poilane 29197 (fl.) (P). Quang Ninh: Vicinity of Ting Wu Shan, Chuk Phai, Ha Coi, 10 Nov. – 17 Nov. 1936, W.T. Tsang 27239 (fl.) (C, GH K, P). Quang Tri: Dong Che, near Quang Tri, 24 May 1924, Poilane 10569 (fl.) (P). Thai Binh: Kieu Son, 26 Jan. 1961, Soviet-Vietnam Expedition 1722 (fl.) (LE). Tuyen Quang: Ha Tuyen, Na Hang, Vinh Yen, Khao Phung, trail between Ban Chou and Nam Ban, 022º 21’04"N, 105º 25’ 35"E, 6 March 1994, Harder et al. 2351 (fl.) (HN, MO). Vinh Phu: Tam Dao, ridge of Tam Dao above hillstation, 25 Aug. 1994, Boyce 819 (fl.) (HN, K).