Lasianthus biflorus (Blume) Gangopadhyay & Chakrabarty (1992:338)

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 : 10

5. Lasianthus biflorus (Blume) Gangopadhyay & Chakrabarty (1992:338) ≡ Litosanthes biflora Blume (1826:994) . Type (lectotype designated by Zhu 2002):— INDONESIA. Java, C. L. Blume s.n. (lectotype L0000722 image!).

= Lasianthus gracilis King & Gamble (1904:132) . Type (lectotype designated by Wong 1988):― MALAYSIA. Perak, Tea Gardens, H. N. Ridley 2904 (lectotype SING0059255 image!).

T hailand: ―CENTRAL. Nakhon Nayok: Khao Yai National Park, 29 September 1974, J. F. Maxwell 74-924 (AAU, BK). SOUTH-EASTERN. Trat: Ban Rai district, 29 November 1924, A. F. G. Kerr 9492 (BK). without locality, A. F. G. Kerr 15221 (AAU, K).

Distribution: ― China (S Yunnan, Hainan, Taiwan), Malaysia (Peninsular, Borneo), Philippines, Indonesia (Sumatra, Java, Kalimantan, Sulawesi, Lesser Sunda Islands), Thailand (Central, South-eastern).

Ecology: ―Moist evergreen forest, under shade trees, along Lamtakong river at an elevation of 100‒ 150 m.

Note: ― Litosanthes biflora Blume was merged into Lasianthus by Zhu (2011), Zhu et al. (2012), Naiki et al. (2015) and Tagane et al. (2017) based on morphological characters as well as phylogenetic analysis ( Smedmark et al. 2014) which placed L. biflorus is the Asian Lasianthus clade, based on samples from Thailand. Here, we accept the transfer of L. biflorus to Lasianthus . The specimen of L. biflorus with perfect fertile and vegetative organs was studied at AAU (J. F. Maxwell 74-924).

Lasianthus biflorus is distinct from other species of Lasianthus by having leaf blades subrhomboid or elliptic-obovate, 1.5‒2.5 × 0.5‒1 cm long, adaxial leaf glabrous, abaxial leaf sparsely hirsute, inflorescences with peduncles 1–4 cm long, hirsute, flowers with pedicels 0.8‒1 cm long, calyx campanulate 1‒1.2 mm long, glabrous, calyx limb 5-lobed, young corolla glabrous outside, drupes ovoid and rectangular in top view, 4‒5 mm diameter, glabrous, 4 pyrenes. In addition, L. biflorus has the smallest size of leaves and flowers in Thai Lasianthus .