Lanonia nuichuaensis Henderson & Nguy

Henderson, Andrew & D ựng, Nguy ễn Qu ốc, 2022, A revision of Lanonia (Arecaceae, Coryphoideae, Livistoninae), Phytotaxa 532 (3), pp. 209-245 : 236-238

16. Lanonia nuichuaensis Henderson & Nguy ễn Quốc Dựng sp. nov. Type:— VIETNAM. Ninh Thuan province, Ninh Hai district, Nui Chua National Park , 11.80N 109.16E, ca. 800 m, 26 October 2009, A. Henderson, Bui Van Than, Nguyen Quoc Dat, & A Ruc Cui 3643 (holotype HN!, isotype NY!). Fig. 16 .

Stems 2.0(1.0–3.0) m long, 3.8(3.5–4.0) cm diameter, solitary or clustered. Leaves number not recorded; ligules 9.5(5.0–14.0) cm long, soon disintegrating into fibers; sheaths and proximalmost part of petioles with scattered, brown scales; petioles 100.0 cm long, 0.6 cm wide at the apex; petiole thorns usually poorly developed, brown or black, more or less regularly arranged on proximalmost part of petiole; hastulas raised, triangular, infolded; leaf blades 68.0(60.0– 76.0) cm wide; costas 12.0 cm long, narrow, with a pulvinus at the apex abaxially, with the numerous segments free to the base except the middle pair joined at their bases; segments 14(13–14) per leaf, not mottled, with minute, reddish-brown scales abaxially, with (on dried specimens) straight margins; middle segments 42.0 cm long, 9.8 cm wide at the apex; apices of middle segments with adaxial splits not much deeper than abaxial ones. Inflorescences 105.0(100.0–110.0) cm long; prophylls and peduncles length not recorded; rachis bracts flattened, splitting apically and laterally, almost woody and scarcely tomentose; rachillae not filiform nor thick and ribbed, sparsely to moderately covered with short, mostly simple, brownish hairs; staminate inflorescences not recorded; pistillate rachises absent; pistillate partial inflorescences 1, branched to 3 orders; pistillate rachillae on proximalmost partial inflorescence 12, 13.5 cm long, 1.2 mm diameter; pistillate flowers length not recorded, with short styles; fruits not recorded; seeds not recorded.

Distribution and habitat:—Southern Vietnam in Ninh Thuan province in Nui Chua National Park in forest on steep, rocky slopes at 775(650-850) m elevation ( Fig. 17 ).

Taxonomic notes:— Four specimens formerly included in L. poilanei (see notes under that species) differ from others by their infolded (versus rounded) hastulas and are here recognized as a separate species, L. nuichuaensis . Quantitatively the two species are rather similar.

One sterile specimen (Regalado 4496) from Nui Chua appears to have long, papery ligules and leaves with few segments with the middle pair wider than the others. On the label, fruits are reported to be white. This specimen remains unidentified.

Figures

FIGURE 16. Type of L. nuichuaensis (Henderson et al. 3643).

FIGURE 17. Distribution maps of L. nuichuaensis, L. poilanei, L. tenuisecta, and L. verrucosa.