Renealmia tchimbeleana Dhetchuvi & Eb.Fisch., 2024

Fischer, Eberhard & Dhetchuvi, Jean-Baptiste M. M., 2024, A revision of the genus Renealmia (Zingiberaceae) in Tropical Africa. I. New species from Central Africa (Cameroon, Rio Muni, Gabon, Democratic Republic of the Congo), and notes on the identity of Renealmia africana, R. congolana, and R. dewevrei, Phytotaxa 674 (1), pp. 55-96 : 78-79

Renealmia tchimbeleana Dhetchuvi & Eb.Fisch. , sp. nov. ( Figs 18–20 , 30).

Type: — GABON. Woleu-Ntem. Crystal Mountains, Tchimbélé , ½ km SE of dam, primary forest on steep hill side, 19 December 1989, J.J. Wieringa 255 (holotype WAG1868012 !; isotype LBV!) .

Diagnosis: —The new species differs from all African species in the short and capitate inflorescence with 1-flowered cincinni. The only other morphologically similar species is the newly described Renealmia longituba (see above), that differs in the many-flowered inflorescence and the much longer calyx.

Description: —Perennial herb forming dense clump. Leafy shoots c. 60 cm tall, covered at base with imbricate leafless sheaths. Leaves papery, with sulcate sheaths surrounding stem, with reticulately anastomosing venation and numerous hairs between reticulations, sparse at base and dense towards apex near ligule. Petiole reticulate, c. 1.5 cm long, hairy between reticulation. Ligule obtuse, up to 2 mm long. Lamina elliptic-lanceolate, asymmetric at base and largely decurrent along entire petiole down to sheath, acuminate at apex, acumen c. 1.5 cm long, glabrous, about 20–25 cm long and 3–5 cm wide, median vein furrowed at base, lateral veins visible at both surfaces but much more prominent on lower surface. Inflorescence thyrsic, arising at base of leafy shoots, c. 7 cm long, with simple and branched hairs; peduncle about 5 cm long, with up to 5 articulations, longest reaching 1.3 cm long, leafless glabrescent sheaths elliptic, basal ones short and superposed, upper ones larger, up to 1.8 cm long, with short and caducous hairs, rachis red. Bracts oblong, about 1 cm long; bracteoles shorter and wider than bracts, about 5 mm long, with dense hairs, tufted at apex; partial inflorescences (cincinni) up to 10 per inflorescence, subsessile, with 1 flower; pedicels dark red, about 1 mm long, regularly enlarged at apex. Calyx persistent, accrescent in fruit, tubular, glabrous except for ciliate margin, purple, about 5–6 mm long in fruit. Corolla and stamen not known. Fruits ellipsoid, dark red c. 1 cm long and 4 mm in diameter. Seeds globose-polygonal to irregular, 3 mm in diameter, 4 per locule.

Distribution: —Only known from the type locality Tchimbele in the Crystal Mts., Gabon.

Habitat: —Primary forest on steep hill, 600 m.

Etymology: —Named after the type locality Tchimbele.

Preliminary IUCN conservation assessment: —With only one site where Renealmia tchimbeleana has been observed, it is not possible to calculate the extent of occurrence (EOO). The area of occupancy (AOO) with 9 km ² meets the criteria of the Critically Endangered category (CR) under sub-criterion B2. One major threat is deforestation, but the only known location lies inside a protected area (Parc National des Monts Crystal). There is only one herbarium sheet collected in 1989, which indicate that it is rare. The species is thus assessed here as Least Concern (LC), Conservation dependent (CD).

Figures

FIGURE 18. Renealmia tchimbeleana. Holotype, WAG. Scale bar: 5 cm. Reproduced with permission from WAG.

FIGURE 19. Renealmia tchimbeleana. A, B. Infructescence. A from Wieringa 255 (WAG); B from Wieringa 255 (LBV). Scale bars: 5 mm. Reproduced with permission from WAG and LBV.

FIGURE 20. Renealmia tchimbeleana. A. Leaf. B. Inflorescence with base of leafy shoot. C. Base of leafy shoot. D, E. Fruits.A–E from Wieringa 255. Illustration by E. Fischer. Scale bars:A. 1 cm; B. 5 cm; C–E. 5 mm.