THAI FOREST BULLETIN (BOTANY) 36
Argyreia confusa (Prain) Raizada, Ind. Forester 93: 754. 1967.— Lettsomia confusa Prain, J. Asiat. Soc. Bengal 63(2): 96. 1894; Kerr, Fl. Siam. 3: 32. 1954. Type. Myanmar. Shan Hills, King’s Collector s.n. (syntype, CAL, n.v.), Makhoye Hill, King’s Collector s.n. (syntype,
Thailand.— NORTHERN: Chiang Mai [Mae Rim distr., Mae Rim to Samueng road, secondary dry dipterocarp forest, 400 m, 7 Sept. 1989, Pooma 329 (BKF), Bo Luang, in disturbed dry dipterocarp forest, 1000 m, 7 June 1973, Geesink et al. 5829 (BKF, L), Doi Suthep, deciduous jungle, 350 m [1100 ft], 20 Nov. 1910, Kerr 1564 (BM), same locality, 26 Aug. 1911, Kerr 1976 (BM), same locality, 5 Oct. 1912, Kerr 1976A (BM)]; Phrae [Me Ban, 29 Sept. 1929, Franck 384 (C, P)]; Phitsanulok [Pong Pa Forest, 300 m, 28 Dec. 1965, S.P. s.n. (BKF 47989); Nakhon Sawan. Wang-chao, 14 Oct. 1904, Hosseus 116 (BM, E, L, P)]; NORTHEASTERN: Phetchabun [Nam Nao National Park, Pha Daeng cliff, open grassy slope, 900–960 m, 26 Dec. 1982, H. Koyama et al. T-31725 (BKF)].
Distribution.— Myanmar, China (Yunnan), Thailand.
D. The continental Asian moonflowers (Ipomoea)
The Asian night-flowering species of Ipomoea (moonflowers) have not been taxonomically studied in the same degree of thoroughness as their tropical American counterparts (e.g. Gunn 1972). With less than 10 taxa, this distinctive night-flowering group of Asian Ipomoea would make a suitable project for a master’s thesis student to undertake. Moonflowers are night-flowering species with a distinctive suite of floral characters: salverform corolla, white in color, sweet fragrance, often exserted stamens and stigma. These conform to a nocturnal moth pollination syndrome that appears multiple times in the genus Ipomoea; thus, it is quite possible that moonflower species are not closely related inter se. The following discussion resolves the name to be used for one of the indigenous Thai moonflowers, until such time as a revision clarifies the relationships among the Asian- Malesian species.
Since 1985, attempts to identify Thai specimens in the moonflower group led to some anomalous results. Specimens are easily dealt with for Ipomoea aculeata Blume, I. alba L., I. muricata (L.) Jacq., and I. violacea L.—the keys in Flora Malesiana (Van Ooststroom & Hoogland 1953) working very well to identify them.Yet a few Thai specimens keyed out intermediate between I. aculeata and I. trichosperma Blume, fitting neither species in respect to critical details of floral morphology. Aside from the morphological ill- fit, there is the astonishing biogeographic disjunction to consider: I. trichosperma is known from several Indonesian islands—Java, Celebes, and the Lesser Sunda Islands and previous reports of it from the Asian continent have been dismissed as incorrect. Van Ooststroom (1940: 580) ruled out the presence of genuine I. trichosperma on the Asian mainland, stating the Clarke (1883: 198) had misapplied the name to specimens of I. aculeata and that Gagnepain & Courchet (1915) had also misapplied the name to some other species, which Van Ooststroom did not identify.
Having no other names available, I nonetheless called these anomalous Thai plants I. trichosperma, and that name was used for them in the recent checklist of Thai Convolvulaceae (Staples et al. 2005). Further research has now brought to light more information and it is possible to provide an unambiguous name for them.