1. Rhapis evansii Henderson sp. nov. Type:— LAOS. Vientiane: Vangvieng district, Ban Nathong, Tham Poukham, 18° 55’N, 102° 24’ E, 250–350 m, 1 August 1999, T. Evans 56 (holotype K!, barcode K000462531). (Fig. 1)

Rhapis evansii differs from all other species except R. puhuongensis and R. vidalii by its pedicellate flowers; it differs from both of these in its elliptic, multi-veined, acuminate central segments with the apices oblique and toothed.

Stems 0.8 m long, 0.5 cm diameter. Leaf sheath fibers coarse, flattened, forming a diagonal mesh, extended into a well-developed ligule; petioles 15.0 cm long, 1.1 mm wide at the apex; abaxial hastula usually complete, a low ridge separating petiole apex from costa; segments 6 per leaf; central segments elliptic, multi-veined, acuminate, the apices oblique, toothed, 23.0 cm long, 2.7 cm wide at midpoint, free almost to the base, the non-split part 0.2 cm; lateral segments 21.0 cm long, 1.0 cm wide at midpoint, the non-split basal part 0.3 cm; abaxial surface of segments without scales, not indumentose when first exposed. Inflorescences slender; prophyll and peduncular bract narrow, tubular, not or scarcely overlapping, the inflorescences exerted apically through the bracts on a curved peduncle; rachis length not recorded; rachillae slender, filiform, usually <1 mm wide; rachillae length not recorded; flowers pedicellate; flowers and fruits not recorded.

Distribution and habitat:—Central Laos in lowland forest on karst limestone outcrops at 250–350 m elevation (Fig. 2).

Taxonomic notes:— Although complete inflorescences and flowers are not known, the species is immediately distinguished by the combination of elliptic segments and pedicellate flowers.