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 46. Lasianthus puffii Napiroon, Balslev & Poopath , sp. nov. ( Figure 1 ). Diagnosis:— Lasianthus puffii is similar to L. cyanocarpus Jack (1823:125) , but differs in having branches and petioles that are densely hirsute and 6‒8 (not 2‒3) mm long, 10‒12 (not 8–10) pairs of secondary veins, densely hirsute (not tomentose), indument on the leaf blade, midrib, stipules, bracts and calyx bracteoles absent (not bractoles present numerous), hirsute with numerous 3‒3.5 mm long hairs on the base of the calyx (not absent), calyx campanulate with 5 lobes, nerved on lobes (not nerves absent), calyx lobes oblong-lanceolate (not linear-lanceolate), 7‒8 (not 3-4) mm long, densely hirsute at base and above sparely hirsute (not tomentose), drupes ellipsoid, narrowed at the base (not ovoid), hirsute (not pilose), calyx limb on fruits with 4‒5 (not 1–2) mm long lobes and fruit with 5 (not 4) pyrenes. Type: ― THAILAND . Phangnga : Khao Lak-Lumru National Park, Ton Chong Fah waterfall, 8 ° 42’59.597”N , 98 ° 15’53.503”E , 21 August 1999 , C. Puff 990821-1/5 ( holotype : BKF! isotype : PSU! WU!). Description: — Shrubs to 1 m tall. Stem terete, 8–10 mm diam., densely hirsute; branches and branchlets terete, 1.5–2 mm diam., densely hirsute, hairs 2–3 mm long. Stipules triangular 3‒4 mm long conspicuous and hidden by large inflorescence bracts, apex acute, densely hirsute. Leaves membranaceous to subcoriaceous; petiole 6‒8 mm long, densely hirsute; blades oblong to oblanceolate, 8–14 × 3–4 cm , base asymmetrical and slightly oblique, apex acute, sparely hirsute on both surfaces, more densely so on the midrib and veins beneath; secondary veins 10–12 pairs, slender, slightly depressed above, prominent beneath, ascending at angles of 45‒50° from midrib, tertiary veins faint above, obvious beneath, subreticulate; inflorescence bracts large, broadly ovate, 2 pairs per node, bracts leaf-like 1.5 cm long, 1 cm wide, apex cuspidate, densely hirsute. Cymes sessile; calyx hirsute, campanulate; calyx tube 3 mm long, densely hirsute at base and sparely hirsute above; calyx 5-lobed, lobes oblong-lanceolate, nerved, 7 mm long, margin hirsute; corolla 3 mm long, corolla tube 1‒1.5 mm long, outside hirsute and inside sparely pilose, 4-lobed, lobes broadly triangular 2 mm long, externally hirsute, internally subglabrous; anthers 4, innate, 0.5 mm long; style 1‒1.5 mm long, 5-lobed, glabrous, stigma 0.2–0.3 mm long. Drupes ellipsoid, 5 mm diam., sparsely hirsute, crowned by very long calyx limb, 4 mm long, hirsute; pyrenes 5, very hard. Common name: —Jed Chang Sarn Yai Phang-nga. Distribution: —Peninsular Thailand , known from Khao Lak-Lumru National park, Ta Kua Pa district, Phangnga province . Habitat : — Growing in shade among understory trees in tropical rainforest, on sandy loam at 400‒1000 m elevation. IUCN conservation assessment: — Lasianthus puffii is here considered as Endangered (B2ab(ii)), in accordance with IUCN categories and criteria ( IUCN, 2012 ). One population has been reported on the specimen description notes as coming from Phangnga province , but, although we have searched for it, we did not find it. These areas are being transformed to para rubber plantation and other land uses. Phenology : — Flowering and fruiting in July–August. Etymology: —The specific epithet is given in honour of the late Prof. Dr. Christian Puff, University of Vienna, Aurtria, who studied Rubiaceae in Thailand and made the first collection of this species in Thailand on 21 August 1999 .