Hemithrinax rivularis León (1941: 380)

Henderson, Andrew, 2023, A revision of Coccothrinax, Hemithrinax, Leucothrinax, Thrinax, and Zombia (Arecaceae), Phytotaxa 614 (1), pp. 1-115 : 93

2.3. Hemithrinax rivularis León (1941: 380) .

Thrinax rivularis (León) Borhidi & Muñiz (1985: 226).

Type:— CUBA. Oriente, oeste de Moa, Arroyo de Centeno , 23 July 1941, León & Clemente 20426 (holotype HAC!, isotypes BH!, US!)

Hemithrinax savannarum León (1941: 381) . Hemithrinax rivularis var. savannarum (León) Muñiz in Muñiz & Borhidi (1982: 312). Thrinax rivularis var. savannarum (León) Borhidi & Muñiz (1985: 226).Type:— CUBA. Oriente, Moa, sabana de aeropuerto, 21 July 1941, León 20101 (holotype HAC!, isotypes BH!, US!).

Stems 1.0 m long and 8.3 cm diameter. Leaf sh eath fibers 0.7–0.8 mm diameter wiry, separating into curled, multi-fiber strands; petioles 15.7(14.4–16.3) mm diameter just below the apex; palmans 35.0(26.5–47.0) cm long; segments 41(39–42) per leaf, the middle ones 65.6(57.0–77.0) cm long and 4.4(3.6–5.6) cm wide; middle leaf segment apices attenuate; leaf segments without or with well-developed transverse veinlets. Inflorescences erect amongst or above the leaves with few to numerous partial inflorescences; rachis bracts tubular, closely sheathing, membranous, brown tomentose; partial inflorescences 5(3–6); proximalmost rachillae straight, 7.8(5.5–12.0) cm long and 1.2(0.9–1.4) mm diameter in fruit; stamens 6; fruit pedicels 0.1–0.2 mm long; fruits 14.2(14.0–14.3) mm long and 13.4(13.0–13.8) mm diameter, yellowish.

Distribution and habitat:— Eastern Cuba (Holguín) ( Fig. 20 ) in wet savannas or pine woods on serpentine soils at 350(300–400) m elevation.

Taxonomic notes:— León (1941) recognized two species, Hemithrinax rivularis and H. savannarum . Hemithrinax rivularis was said to differ by its larger stems, longer petioles, subglobose fruits, and details of the seeds. León noted that H. rivularis occurred in wooded areas and H. savannarum in more open, savanna areas. The two species were recognized at the varietal level by Muñiz & Borhidi (1982). The two varieties are not recognized here. There is no geographic separation between the two, and too few specimens to test for differences.

Leaf segments are scored as with or without or with poorly developed transverse veinlets but this is difficult to score.

Figures

FIGURE 20. Distribution of Hemithrinax ekmaniana, H. compacta, and H. rivularis.