Lanonia batoensis Henderson & Nguy

Henderson, Andrew & D ựng, Nguy ễn Qu ốc, 2022, A revision of Lanonia (Arecaceae, Coryphoideae, Livistoninae), Phytotaxa 532 (3), pp. 209-245 : 223

2. Lanonia batoensis Henderson & Nguy ễn Quốc Dựng (2017: 159). Type:— VIETNAM. Quang Ngai, Ba To District, road from Ba To to Ba Cung , 14°44’N 108°53’E, ca. 600 m, 18 July 2012, A . Henderson, Nguyễn Qu ốc Dựng & Le Van Tuan 3818 (holotype VFM!, isotype NY!) .

Stems 1.8 m long, 3.0 cm diameter, solitary. Leaves 12 per stem; ligules 1.6(1.5–1.7) cm long, soon disintegrating into fibers; sheaths and proximalmost part of petioles without scales; petioles 85.0 cm long, 0.6(0.5–0.7) cm wide at the apex; petiole thorns usually poorly developed, brown or black, more or less regularly arranged on proximalmost part of petiole; hastulas flat, rounded, not infolded; leaf blades 65.0 cm wide; costas 3.2(3.0–3.3) cm long, triangular, with a pulvinus at the apex abaxially, with the numerous segments free almost to the base; segments 20(19–20) per leaf, not mottled, without minute, reddish-brown scales abaxially, with (on dried specimens) straight margins; middle segments 52.0(50.5–53.5) cm long, 1.3(1.0–1.6) cm wide at the apex; apices of middle segments with adaxial splits much deeper than abaxial ones. Inflorescences 122.5(115.0–130.0) cm long; prophylls and peduncles length not recorded; rachis bracts tubular, splitting apically, not densely tomentose; rachillae not filiform nor thick and ribbed, sparsely to moderately covered with short, mostly simple, brownish hairs; staminate rachises not recorded; staminate partial inflorescences 6, branched to 3 orders; staminate rachillae number and length not recorded, 0.9 mm diameter; staminate flowers not recorded; pistillate rachises absent; pistillate partial inflorescences 1, branched to 3 orders; pistillate rachillae on proximalmost partial inflorescence 18, 18.4 cm long, 1.3 mm diameter; pistillate flowers length and styles not recorded; fruits not recorded; seeds not recorded.

Distribution and habitat:—Central Vietnam in Quang Ngai province, Ba To District, in lowland rainforest at 600 m elevation ( Fig. 8 ).

Taxonomic notes:— Specimens determined as preliminary species Lanonia batoensis share a unique combination of qualitative variable states and are therefore recognized as a phylogenetic species.

Lanonia batoensis is notable for its sheaths and proximalmost part of petioles without scales, narrow leaf segments without minute, reddish-brown scales abaxially, large, erect inflorescences projecting above the leaves, and tubular, apically splitting, not densely tomentose rachis bracts.

Figures

FIGURE 8. Distribution maps of L. acaulis, L. batoensis, L. calciphila, and L. centralis.