Lanonia manglaensis (Henderson, Ninh Khac Ban & Nguyễn Quốc Dựng) Henderson & Nguyễn Quốc Dựng

Henderson, Andrew & D ựng, Nguy ễn Qu ốc, 2022, A revision of Lanonia (Arecaceae, Coryphoideae, Livistoninae), Phytotaxa 532 (3), pp. 209-245 : 235

14. Lanonia manglaensis (Henderson, Ninh Khac Ban & Nguyễn Quốc Dựng) Henderson & Nguyễn Quốc Dựng (2017: 165).

Licuala manglaensis Henderson , Ninh Khac Ban & Nguyễn Qu ốc Dựng (2008: 153). Type:— VIETNAM. Kon Tum, Kon Plong Distr., Hieu Commune, Mang La Forest Enterprise , 14°39’N 108°25’E, 1,100–1,200 m, 16 April 2000, L. Averyanov et al. VH 5201 (holotype HN!, isotype MO!) .

Stems 1.8(1.5–2.5) m long, 1.7(1.4–2.0) cm diameter, solitary. Leaves 16(16-17); ligules 6.4(5.5–7.0) cm long, papery, not disintegrating into fibers; sheaths and proximalmost part of petioles with dense, flat, black scales; petioles 34.0(28.0–40.0) cm long, 0.3(0.2–0.3) 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 flat, rounded, not infolded; leaf blades 23.5(22.0–25.0) cm wide; costas 16.4(14.0–18.5) cm long, continuous to apex of leaf, without an abaxial pulvinus; segments 5 per leaf, not mottled, with minute, reddish-brown scales abaxially, with (on dried specimens) straight margins; middle segments 16.4(14.0–18.5) cm long, 3.7(2.5–4.7) cm wide at the apex; apices of middle segments with adaxial splits much deeper than abaxial ones. Inflorescences 56.7(40.0–80.0) cm long; prophylls 11.5 cm long; peduncles 59.5 cm long; rachis bracts narrowly tubular, splitting apically, not or sparsely tomentose; rachillae filiform, densely covered with erect, branched, translucent hairs; staminate rachises absent; staminate partial inflorescences 1, branched to 3 orders; staminate rachillae 11(8–13), 7.9(7.5–8.8) cm long, 0.6(0.4–0.7) mm diameter; staminate flowers 1.8(1.7–2.0) mm long; sepals not pedicellate at the base, densely hairy; petals rounded at the apex; stamens with alternately long and short filaments and small, almost square anthers; filaments not elongate; pistillodes undivided; pistillate rachises absent; pistillate partial inflorescences 1, branched to 2–3 orders; pistillate rachillae on proximalmost partial inflorescence 6(5–7), 6.8(4.8–8.8) cm long, 1.0(0.9–1.0) mm diameter; pistillate flowers 1.8(1.2–2.3) mm long, with short styles; fruits not recorded; seeds not recorded.

Distribution and habitat:— Southern Vietnam in Kon Tum province, known only from a small area in Kon Plong district, in montane rainforest at 1,198(1,140 –1,468) m elevation ( Fig. 14 ).

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

Lanonia manglaensis is notable for its middle segments joined along their entire length into a single segment (hence the middle segment width given above represents half the total middle segment width). Although other species occasionally have individuals with completely joined middle segments, in L. manglaensis they are consistently joined and there is no abaxial pulvinus at the apex of the costa, as in other species. All seven specimens examined have five segments per leaf.

Lanonia manglaensis has papery ligules, sheaths and petioles with flat, black scales, petioles with stout, reddishbrown thorns, rounded hastulas, and apices of the middle segments with adaxial splits much deeper than the abaxial ones. In these it resembles L. hexasepala and related species. It also shares with L. hexasepala noticeably dark brown stems.

Figures

FIGURE 14. Distribution maps of L. kontumensis, L. magalonii, L. manglaensis, and L. montana.