Lasianthus purpureocalyx Napiroon et al. (2018a:84)

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 : 25-26

47. Lasianthus purpureocalyx Napiroon et al. (2018a:84) . Type: ― THAILAND. Krabi, Khao Ngon Nak, 23 August 2017, T. Napiroon et al. TN030 (holotype BKF!). ( Figure 3 Aa).

T hailand: ―PENINSULAR. Krabi:Aaonang sub-district, Khao Ngon Nak, 23 August 2017, T. Napiroon et al. TN 031 (BKF). Songkhla: Khao Nam Khang, 28 January 2006, S. Gardner ST2265 (BKF, K). Nakhon Si Thammarat: Chang Klang, 11 July 2000, V. Chamchumroon VC840 (BKF).

Distribution: ―Endemic to Thailand (Peninsular).

Ecology: ―This species was found in shade under trees in tropical rain forest, on metamorphic or granitic rock substrates at an elevation of 100‒ 500 m.

Note: ― Lasianthus purpureocalyx is similar to L. subcalvus and L. subaureus . It differs from L. subcalvus by having densely appressed pubescence on branches (not glabrous), the calyx is tubular with limb shallowly curved (not campanulate), corolla lobes 6‒7 (not 4), narrowly lanceolate (not ovate-lanceolate). It differs from L. subaureus by having 7‒8 (not 11‒12) pairs of lateral veins, petioles 3‒5 (not 11‒12) mm long, calyx tubular with 4 lobes shallowly curved (not calyx cupulate or truncate), corolla with 6‒7 (not 5‒6) lobes, pyrenes 4‒5 (not 5‒6).

Figures

FIGURE 3A‒O. Lasianthus werefound in Thai naturalforests:A) L. appressus;B) &C) L.attenuatus;D) L.chinensis;E) L.chrysoneurus; F) L. constrictus; G) L. cyanocarpus; H) L. ellipsoideus; I) L. ellipticus; J) L. fordii; K) L. foxworthyanus; L) & M) L. hirsutus; N) L. hispidulus and O) L. inodorus.