Rhapis robusta Burret (1937: 587)

Henderson, Andrew, 2016, A revision of Rhapis (Arecaceae), Phytotaxa 258 (2), pp. 137-152 : 147-148

9. Rhapis robusta Burret (1937: 587) . Lectotype (here designated):— CHINA. Kwangsi : Lungchow, 7 July 1935, S. Ko 55429 (lectotype IBSC!)(the holotype at B was destroyed)

Stems 1.5 m long, 0.7(0.6–0.8) cm diameter. Leaf sheath fibers coarse, flattened, forming a diagonal mesh, extended into a well-developed ligule; petioles 29.7(20.0–43.0) cm long, 2.2(1.7–3.0) mm wide at the apex; abaxial hastula usually complete, a low ridge separating petiole apex from costa; segments 5(2–8) per leaf; central segments elliptic, usually multi-veined, acuminate, the apices oblique, toothed, 21.5(15.7–27.0) cm long, 3.1(1.8–4.2) cm wide at midpoint, joined at the base, the non-split basal part 3.3(1.4–5.3) cm; lateral segments 19.8(15.7–24.0) cm long, 2.2(1.9–2.7) cm wide at midpoint, the non-split basal part 1.9(1.0–2.7) cm; abaxial surface of segments without scales, not indumentose when first exposed. Inflorescences slender, few branched, with the first branch not as large as the rest of the inflorescence; 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 filiform, usually tomentose, especially the staminate ones; proximal rachilla 6.2(4.0–7.4) cm long, 0.6(0.4–0.8) mm wide; staminate and pistillate flowers sessile; staminate and pistillate corollas with poorly developed, inturned apical lobes, these not swollen internally; filaments keeled; fruits color and size not recorded, borne on a pedicelliform pistillate corolla.

Distribution and habitat:—Northern Vietnam (Cao Bang, Ha Giang) and adjacent China (Guangxi)( Fig. 5 ) in lowland forest on limestone soils at 500(400–700) m elevation.

Taxonomic notes:— The segments of Rhapis robusta have scarcely toothed apices and they appear almost acuminate.

Figures

FIGURE 5. Distribution maps of Rhapis robusta, R. subtilis subsp. subtilis, R. subtilis subsp. siamensis, and R. vidalii.