A synopsis of Lasianthus (Lasiantheae, Rubiaceae) in Thailand and two additional new species Author Napiroon, Tiwtawat 0000-0002-4710-5016 Biology major, Faculty of Science & Technology, Pibulsongkram Rajabhat University, Phitsanulok 65000, Thailand napiroont@gmail.com Author Chayamarit, Kongkanda 0000-0003-1057-6380 The Forest Herbarium (BKF), Department of National Parks, Wildlife and Plant Conservation, Bangkok, 10900, Thailand kchayamarit@gmail.com Author Dawson, Sally 0000-0002-8178-0912 Identification and Naming Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW 9 3 AE, United Kingdom S.Dawson@kew.org Author Till, Walter 0000-0001-9329-4340 Department of Botany and Biodiversity Research, Faculty of Life Science, University of Vienna, Rennweg 14, A- 1030, Austria walter.till@univie.ac.at Author Balslev, Henrik 0000-0002-7101-7120 Section Ecoinformatics and Biodiversity, Department of Bioscience, Faculty of Science and Technology, Aarhus University, Aarhus 8000, Denmark henrik.balslev@bios.au.dk text Phytotaxa 2020 2020-04-15 439 1 1 38 http://dx.doi.org/10.11646/phytotaxa.439.1.1 journal article 10.11646/phytotaxa.439.1.1 1179-3163 13873503 1. Lasianthus appressus Hooker (1880:181) . Type: ( lectotype designated by Zhu 2012 ):― MALAYSIA . Peninsular Malaysia, without locality, W. Griffith 2927 ( lectotype K000763936!). ( Figure 3A ). Thailand :―PENINSULAR. Nakhon Si Thammarat : Khao Luang National Park, 23 June 1970 , T. Shimizu & A. Nalampoon T8220 (BKF, K), 5 October 1986 , P. Sirirugsa PS1034 (BKF, PSU ), 24 October 1993 , K. Larsen et al. 43946 (AAU, BKF, K, PSU ), 27 February 2006 , S. Gardner & P. Sidisunthorn ST2386 (BKF, K). Phatthalung : Khao Bantad Wildlife Sanctuary, 24 October 1993 , K. Larsen et al. 43946 (AAU, BKF, PSU ). Satun : Thale Ban National Park, 13 September 1990 , C. Puff & V. Urchirakal 900913-1/6 (BKF, WU ), 4 November 1990 , K. Larsen et al. 41108 (AAU, BKF, PSU ). Songkhla : Tone Nga Chang Wildlife Sanctuary, 25 September 1997 , Puangpen N047 ( QBG ). FIGURE 3 A‒O. Lasianthus were found in Thai natural forests: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 . Distribution: ―Peninsular Malaysia , Thailand (Peninsular), Singapore . Ecology: ―Moist evergreen forest, in shaded places on sandy-loam at an elevation of 50– 900 m . Flowering in August and fruiting in September. Notes: ― Lasianthus appressus is distinct from other species of the genus in having relatively small leaves, branches appressed-hirsute, and drupes with eight pyrenes. These can be easily observed when dry, both in the field and on herbarium specimens.