10. Lanonia honbaensis Henderson & Nguy ễn Quốc Dựng sp. nov. Type:— VIETNAM. Khanh Hoa province, Dien Khanh district, Hon Ba Nature Reserve, 12.116N 108.933E, 1,445 m, 11 July 2010, A. Henderson, Bui Van Thanh & Nguyen Thi Bich Ngoc 3705 (holotype HN!, isotype NY!). Fig. 11 .

Stems 2.3(1.5–4.0) m long, 3.5(2.5–5.0) cm diameter, solitary. Leaves 13; ligules 20.8(15.0–26.5) cm long, papery, not disintegrating into fibers; sheaths and proximalmost part of petioles with dense, flat, black scales; petioles 77.5(60.0– 90.0) cm long, 0.6(0.6–0.7) cm wide at the apex; petiole thorns usually stout, reddish-brown or dark brown, some bifid or often some in pairs, on proximalmost part of petiole; hastulas raised, triangular, infolded; leaf blades 55.0(50.0– 60.0) cm wide; costas 3.8(2.0–5.7) cm long, triangular, with a pulvinus at the apex abaxially, with the numerous segments free almost to the base; segments 16(13–19) per leaf, mottled or not mottled, with minute, reddish-brown scales abaxially, with (on dried specimens) straight margins; middle segments 30.3(26.0–35.0) cm long, 7.1(3.7–11.1) cm wide at the apex; apices of middle segments with adaxial splits much deeper than abaxial ones. Inflorescences 60.0 cm long; prophylls 15.0 cm long; peduncles 38.0 cm long; rachis bracts flattened, splitting apically and laterally, usually densely brown 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 2–3 orders; pistillate rachillae on proximalmost partial inflorescence 14(6–19), 12.4(10.2–15.5) cm long, 1.1(1.0–1.2) mm diameter; pistillate flowers length not recorded, with short styles; fruits not recorded; seeds not recorded.

Distribution and habitat:— Southern Vietnam in Khanh Hoa province, known only from Hon Ba Nature Reserve, in montane rainforest at 1,512(1,445 –1,578) m elevation (Fig. 10).

Taxonomic notes:— Four s pecimens formerly included in Lanonia hexasepala (see notes under that species) differ from others by their raised, triangular, infolded (versus rounded) hastulas, and are here recognized as a separate species, L. honbaensis . Although staminate inflorescences and fruits are not recorded, L. honbaensis differs quantitatively from L. hexasepala and has considerably higher mean values for all recorded variables.