Lanonia magalonii (Henderson, Ninh Khac Ban & Nguyễn Quốc Dựng) Henderson & Bacon (2011: 893)

Henderson, Andrew & D ựng, Nguy ễn Qu ốc, 2022, A revision of Lanonia (Arecaceae, Coryphoideae, Livistoninae), Phytotaxa 532 (3), pp. 209-245 : 232-234

13. Lanonia magalonii (Henderson, Ninh Khac Ban & Nguyễn Quốc Dựng) Henderson & Bacon (2011: 893) .

Licuala magalonii Henderson , Ninh Khac Ban & Nguyễn Qu ốc Dựng (2008: 152). Type:— VIETNAM. Da Nang City , Hoa Vang District , Ba Na-Nui Chua Nature Reserve , 20 April 2007, A. Henderson, Nguyễn Qu ốc Dựng, Nguyen Canh, & Le Van Bo 3304 (holotype HN!, isotype NY!) .

Stems 0.7(0.3–1.5) m long, 2.3(2.0–2.5) cm diameter, solitary or clustered. Leaves 9(6–12) per stem; ligules 7.0 cm long, soon disintegrating into fibers; sheaths and proximalmost part of petioles with scattered, brown scales; petioles 38.7(33.0–43.0) cm long, 0.5(0.3–0.6) cm wide at the apex; petiole thorns usually poorly developed, brown or black, more or less regularly arranged on proximalmost part of petiole; hastulas flat, rounded, not infolded; leaf blades 46.0(44.0–48.0) cm wide; costas 10.2(6.3–16.2) cm long, narrow, with a pulvinus at the apex abaxially, with the few segments free except the middle pair joined at their bases; segments 4(3–6) per leaf, not mottled, with minute, reddish-brown scales abaxially, with (on dried specimens) straight margins; middle segments 31.3(23.5–38.5) cm long, 13.5(11.0–17.0) cm wide at the apex; apices of middle segments with adaxial splits not much deeper than abaxial ones. Inflorescences length not recorded; prophylls 18.2(16.2–22.0) cm long; peduncles 33.5(26.0–47.0) 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 rachises absent or 11.5 cm long; staminate partial inflorescences 1–2, branched to 2-3 orders; staminate rachillae 4(3–5), 10.0(9.5–11.0) cm long, 1.4(1.1–1.6) mm diameter; staminate flowers 3.0 mm long; sepals not pedicellate at the base, not 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(2–9), 6.1(5.0–7.2) cm long, 1.4(1.1–1.7) mm diameter; pistillate flowers length not recorded, with short styles; fruits 7.3 mm long, 7.4 mm diameter, globose, color not recorded, with rough, pebbled surfaces; seeds with a curved basal intrusion.

Distribution and habitat:— Central Vietnam in Thua Thien-Hue province in Bac Ma National Park, and Da Nang City in Ba Na-Nui Chua Nature Reserve, in montane rainforest at 1,193(800-1,363) m elevation ( Fig. 14 ).

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

Lanonia magalonii appears to be without obvious relatives. Hastulas are difficult to score; they are here scored as open and flat but some specimens appear almost infolded, perhaps by uneven pressing of the leaves.

Subspecific variation:— Lanonia magalonii occurs at higher elevations— 1,100 m on Ba Na-Nui Chua and 800– 1,363 m on Bach Ma—and the two mountains are separated from each other by a ca. 20 km lowland area. Specimens from the two mountains differ significantly from each other in two variables (petiole width, middle segment length) (t –test, P <0.05), with specimens from Ba Na–Nui Chua having lower values. Although there are too few specimens to test, those from Ba Na-Nui Chua have clustered stems 0.3–0.5 m long with 6-8 leaves per stem and 2–4 pistillate rachillae while those from Bach Ma have solitary stems 1–1.5 m long with 12 leaves per stem and 7–9 pistillate rachillae.

Sometimes plants in the field have been observed to have undivided middle segments.

Figures

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