Lasianthus formosensis Matsumura (1901:17)

Napiroon, Tiwtawat, Chayamarit, Kongkanda, Dawson, Sally, Till, Walter & Balslev, Henrik, 2020, A synopsis of Lasianthus (Lasiantheae, Rubiaceae) in Thailand and two additional new species, Phytotaxa 439 (1), pp. 1-38 : 15-16

20. Lasianthus formosensis Matsumura (1901:17) . Type: ― CHINA. Taiwan, no date, Y. Tashiro & S. Tanaka 131

(holotype TI n.v.)

= Lasianthus incomptus Craib (1933:21) . Type: ― THAILAND. Chanthaburi: Khao Soi Dao , 12 December 1924, A. F. G. Kerr 9618 (holotype K000777028!; isotype E00327853 image!).

Thailand: ―NORTHERN. Chiang Mai: s. d., K. Bunchuai 1478 ( BKF). CENTRAL. Nakhon Nayok: Khao Yai National Park, s. d., G. Murata et al. T-52639 ( BKF). PENINSULAR. Phangnga: Khao Phorta Luang Keaw, 2 May 1973, R. Geesink & T. Santisuk 5141 (AAU, BKF, L).

Distribution: ― China (Guangdong, Guangxi, Hainan, Taiwan, Yunnan), Japan (Kyushu, Ryukyu Islands, Yakushima), Vietnam, Thailand (Northern, Central, South-eastern, Peninsular).

Ecology: ―Evergreen forests in shaded places at an elevation of 500‒1000 m. Flowering and fruiting in February‒ May.

Notes: ― Lasianthus formosensis was described in 1901 by Matsumura who deposited his types and worked at the University of Tokyo Herbarium (TI). The type mentioned in the protologue (Y. Tashiro & S. Tanaka 131) was, however, not located by Zhu (2002). We have not found this type specimen in the TI database. Here, we have compared the morphological characters of the Thai specimens identified as L. formosensis above with the original description and we have compared them to the type of L. incomptus which has been cited as a synonym of L. formosensis in the World Checklist of Selected Plant Families (http://wcsp.science.kew.org/). Without having seen the type of L. formosensis , we conclude that it occurs in Thailand based on the mentioned evidence.

In Thailand, Lasianthus formosensis is similar to L. curtisii but it differs by having leaf blades oblong or ovate-elliptic, with 6‒7 pairs of lateral veins and the calyx mostly campanulate. L. curtisii has leaf blades ovate-lanceolate or elliptic-lanceolate, with 4‒6 pairs of lateral veins and the calyx obconical and the calyx lobes divided nearly to the base. However, L. formosensis is also related to L. flavi-hirtus and L. loeiensis . Only the types were seen in AAU and online on the L database. Previously, the two species were erronneously treated as synonyms of L. formosensis . In 2002, Zhu revised these specimens and separated them as to two diferent species, L. flavi-hirtus and L. loeiensis . Lasianthus flavi-hirtus differs from L. formosensis by having flavi-hirsute hairs on branches and branchlets, midrib and calyx, while L. formosensis has brown pubescence on those organs. Lasianthus loeinsis Zhu (2003:576) differs by having linear-lanceolate stipules and linear bracts while L. formosensis has triangular stipules and no bracts.