New species of Lanonia, Licuala, and Pinanga (Arecaceae) from Vietnam Author Henderson, Andrew Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458 - 5126, U. S. A. Author Dung, Nguyen Quoc Forest Inventory and Planning Institute, Thanh Tri, Hanoi, Vietnam text Phytotaxa 2017 2017-09-29 323 2 159 172 http://dx.doi.org/10.11646/phytotaxa.323.2.4 journal article 10.11646/phytotaxa.323.2.4 1179-3163 13696684 Pinanga spiralis Henderson & Nguyen Quoc Dung sp. nov. ( Fig. 11 ). Type:— VIETNAM . Khanh Hoa : Khanh Vinh District, road from Nha Trang to Da Lat, 12.233N , 108.766E , 605 m , 7 July 2010 , A . Henderson & Bui Van Thanh 3678 ( holotype HN !, isotype NY !). It differs from other species of Pinanga in Vietnam with spirally arranged triads ( P. cattienensis , P. nuichuaensis ) in its leaf sheaths forming a crownshaft and multifold pinnae. Stems clustered, 0.5–6.0 m tall, 1.5–3.0 cm diameter, green, covered with scattered reddish-brown scales. Leaves 7; sheaths closed and forming crownshafts, 30.0 cm long, green or yellowish-green, with brown scales; ocreas 1.5 cm long, appearing as two ‘ears’ either side of sheath, early deciduous; petioles 60.0–130.0 cm long, green; rachises 60.0–200.0 cm long; pinnae 8–30 per side of rachis, lanceolate, slightly contracted at the bases, regularly arranged, distantly spaced, multifold, with prominent, raised veins adaxially; middle pinna 48.5–53.0 cm long, 2.7–3.5 cm wide, apical pinna 30.0 cm long, 2.4–3.4 cm wide at the middle, praemorse. Inflorescences infrafoliar, pendulous; peduncles 1.5–2.0 cm long, 1.0 cm wide; prophylls not seen; rachises 0.5 cm long; rachillae 3–6, 11.5–15.0 cm long, glabrous; triads spirally arranged; staminate flowers not seen; pistillate flowers to 3 mm long; sepals to 2.0– 2.5 mm long, imbricate, rounded at the apices, minutely ciliate; petals to 3.0 mm long, imbricate, minutely ciliate; fruits 1.5 cm long, 0.6 cm diameter, ellipsoid, reddish at maturity; endosperm ruminate. Distribution and habitat :—Southern Vietnam in Dak Lak , Khanh Hoa , and Lam Dong provinces in lowland rainforest at 203–550 m elevation. Taxonomic notes:— Two other species of Pinanga in Vietnam ( P. cattienensis , P. nuichuaensis ) have spirally arranged triads. Pinanga cattienensis differs from P. spiralis in having poorly developed crownshafts with the inflorescences pushing through the disintegrating leaf sheaths. Pinanga nuichuaensis differs in its single-fold pinnae. The single specimen examined from Hon Heo, a mountain near Nha Trang, is somewhat tentatively included here; it is considerably smaller than the others. Additional specimens examined . VIETNAM . Khanh Hoa : Ninh Hoa District , Tien Du commune, Hon Heo mountain , 12.450N , 109.233E , 334 m , 6 July 2010 , Henderson & Bui Van Thanh 3669 ( HN , NY ) ; Dien Khanh District , Hon Ba Nature Reserve , 12.116N , 109.000E , 203 m , 9 July 2010 , Henderson & Bui Van Thanh 3692 ( HN , NY ) ; Khanh Vinh district , Khanh Trung commune, Suoi Ca village , road from Khanh Vinh to hydroelectric site, 12.336N , 108.855E , ca. 500 m , 20 April 2013 , Henderson & Nguyen Quoc Dung 3865 ( NY , VFM ) ; Hon Ba Nature Reserve , road to summit, 12.11N , 108.98E , ca. 500 m , 6 July 2014 , Henderson & Nguyen Quoc Dung 3915 ( NY , VFM ) ; same locality, 12.108N , 108.989E , ca. 600 m , 7 July 2014 , Henderson & Nguyen Quoc Dung 3920 ( NY , VFM ) ; new road from Nha Trang to Da Lat , 12.232N , 108.775E , ca. 550 m , 9 July 2014 , Henderson & Nguyen Quoc Dung 3937 ( NY , VFM ) .