Renealmia longituba 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 : 70

Renealmia longituba Dhetchuvi & Eb.Fisch. , sp. nov. ( Figs 12–14 , 30).

Type: — GABON. Estuaire, Monts de Cristal, Nkah NE Mela, 1 February 1968, N. Hallé & J.F. Villiers 4838 (holotype P MNHN-P- P 00072214!).

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 tchimbeleana (see below), which differs in the few-flowered inflorescence and the much shorter calyx.

Description: —Perennial herb forming dense clump. Leafy shoots to 100 cm tall, with c. 8 leaves, glabrous. Leaves with sulcate sheaths surrounding stem, with reticulately anastomosing venation and glabrous. Petiole reticulate, 3–4 cm long, with hairs between reticulations. Ligule obtuse, up to 1 mm long, hairy. Lamina elliptic, attenuate at base and decurrent along petiole, acuminate at apex, acumen c. 1 cm long, about 25–35 cm long and 6–8 cm wide, lateral veins visible at both surfaces. Inflorescence thyrsic, arising at base of leafy shoots, not exceeding 12 cm long, entirely pubescent; peduncle with c. 0.12 cm long articulations about 3 cm long, with weakly coriacous and caducous sheaths. Bracts caducous, membranaceous; bracteoles caducous, membranaceous; partial inflorescences (cincinni) subsessile, with 3 flowers; pedicels about 10 mm long. Calyx persistent, red, accrescent in fruit, tubular, about 10 mm in fruit. Corolla and stamen not known. Fruits numerous, globose to ellipsoid, pubescent, shining black at maturity, 7–8 mm long and 5 mm in diameter, indehiscent, with longitudinal veins well visible. Seeds irregular, c. 4 mm in diameter, 2–3 per locule, orange.

Distribution: —Only known from the type collection in the Crystal Mts. in Gabon.

Habitat: —Submontane rainforest.

Etymology: —The specific epithet refers to the long tube of the calyx.

Preliminary IUCN conservation assessment: —With only one site where Renealmia longituba 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 1968, which indicates that it is rare. The species is thus assessed here as Least Concern (LC), Conservation Dependent (CD).

Figures

FIGURE 12. Renealmia longituba. Holotype, P. Reproduced with permission from P.

FIGURE 13. Renealmia longituba. A, B. Infructescence. C. Fruit. A–C from Hallé & Villiers 4838. Scale bars: A–C. 1 cm. Reproduced with permission from P.

FIGURE 14. Renealmia longituba. A. Leaf. B. Infructescence with base of leafy shoot. C–E. Fruits. A–E from Hallé & Villiers 4838. Illustration by E. Fischer. Scale bars: A. 5 cm; B–E. 1 cm.