Pinanga spiralis Henderson & Nguyen Quoc Dung 2017, sp. nov.
Creators: name: Henderson, Andrew
name: Dung, Nguyen Quoc
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Arecales
Arecaceae
Pinanga
Pinanga spiralis

description: 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).
description: Published as part of Henderson, Andrew & Dung, Nguyen Quoc, 2017, New species of Lanonia, Licuala, and Pinanga (Arecaceae) from Vietnam, pp. 159-172 in Phytotaxa 323 (2) on pages 170-171, DOI: 10.11646/phytotaxa.323.2.4, http://zenodo.org/record/13696684