Renealmia ewangoi Eb.Fisch. & Dhetchuvi, 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 : 59-64

Renealmia ewangoi Eb.Fisch. & Dhetchuvi , sp. nov. ( Figs 3–6 , 28).

Type: —D.R. CONGO. Forestier Central, Haut Zaïre, Ituri. Okapi Wildlife Reserve, Ituri Forest, in 10-ha study area no. 1 at Lenda, July 1996, I.B. Liengola & E.N. Ewango B-51 (holotype BR0000009294479!, isotype C).

Diagnosis: —The new species ressembles the recently described Renealmia timmiorum but differs in the ovate-lanceolate leaves with distinct acumen (elliptic without acumen in R. timmiorum ), and the cup-shaped bracteoles (tubular in R. timmiorum ).

Description: —Perennial herb forming dense clump. Leafy shoots 60–100(–00) cm tall, covered at base with imbricate leafless sheaths. Leaves with sulcate sheaths surrounding stem, without reticulately anastomosing venation. Petiole 2–6 cm long. Ligule obtuse, up to 2 mm long. Lamina coriaceous, obovate to lanceolate, attenuate at base, caudateacuminate at apex, about 12–20 cm long and 3.5–5.5 cm wide, slightly purple at lower surface, lateral veins visible only at lower surfaces. Inflorescence thyrsic, arising at base of leafy shoots, red, 16–21(–30) cm long; peduncle about 10–20 cm long, with up to 6 leafless glabrous sheaths of about (2.1–)5–7 × 0.5 cm, rachis about 1/3 of inflorescence, glabrous, red. Bracts persistent, membranaceous, glabrous, about (3–) 4–12 mm long and 3–4 mm wide; bracteoles persistent, membranaceous, glabrous, about (1–) 2–7 mm long and 2 mm wide; partial inflorescences (cincinni) subsessile, with 1 flower; pedicels purple, glabrous, about 4–9 mm long, only slightly enlarged at apex. Calyx persistent, tubular, glabrous, purple, 7–8 mm, 3–5 mm wide at apex. Corolla white with purplish to violaceous marks, upper petal rounded, 2–5 mm long, tinged with mauve, labellum white with purple, about 5–6 mm long. Stamen with 1 bilocular theca, about 2 mm long. Ovary 5 × 1–2 mm, glabrous, green tinged with purple, style 5 mm long, stigma bilobed. Fruits elongate, glabrous, ca. 7 × 2–3 mm. Seeds not mature, 2–3 per locule, aril white.

Distribution: —Only known from Okapi Wildlife Reserve in the Ituri region in D.R. Congo, from Monte Alen National Park in Rio Muni ( Equatorial Guinea), and adjacent Crystal Mountains National Park and from Doudou Mountains in Gabon.

Habitat: —In Gilbertiodendron dewevrei -dominated forest, and in rainforest on inselbergs and rock outcrops, 430–1100 m.

Etymology: —Named after the Corneille E.N. Ewango who collected the type specimen.

Preliminary IUCN conservation assessment: —The extent of occurrence (EOO) falls within the limits for the Vulnerable status under the sub-criterion B1, whereas its area of occupancy (AOO) is within the limits for the Endangered status. The three locations show a disjunct distribution and are all situated in protected areas. As no details of possible threats and population sizes are known, the species is assessed here as Least Concern (LC).

Additional specimens examined (Paratypes): — RIO MUNI ( EQUATORIAL GUINEA). Parc National de Monte Alen , dalles rocheuses de Monte Alen, à 1h30 de marche du site ECOFAC de Monte Alen, 1100 m, 27 May 2002, I. Parmentier & Esono 3426 (BRLU) ; Parc National de Monte Alen , dalle rocheuse d’Engong, 5 km à l’ouest du village Engong, 1080 m, 10 May 2002, I. Parmentier & Esono 2993 bis (BRLU) .

GABON. Monts de Cristal, SEEF logging concession. Transect 6, mature forest with Coula edulis and Caesalpiniaceae , 580 m, 23 October 2011, T. Stévart, R. Niangadouma, E. Akouangou & J. Kaparadi 3556 (MO, LBV); Ogooue-Maritime, Doudou Mountains National Park, c. 50 km S of Mandji, 430 m, 15 November 2005, M. Sosef, T.I.P. Couvreur, M. Boterman, Y.A. Issembé & R. Niangadouma 2299 (WAG1867937).

Figures

FIGURE 3. Renealmia ewangoi. Holotype, BR. Reproduced with permission from BR.

FIGURE 4. Renealmia ewangoi. A, C. Detail of inflorescence. B. Detail of infructescence. A–B from Liengola & Ewango B 51; C from Parmentier & Esono 2993bis, BRLU. Scale bar: A–C. 1 cm. Reproduced with permission from BR and BRLU.

FIGURE 5. Renealmia ewangoi. A. Inflorescence and base of leafy shoot. B. Inflorescence. Photographs: T. Stévart from Stévart et al. 3556. Reproduced with permission.

FIGURE 6. Renealmia ewangoi. A, B. Leaves. C. Inflorescence. D. Infructescence. E, G. Fruits. F. Cincinnus with flower. A–G from Liengola & Ewango B-51. Illustration by E. Fischer. Scale bars: A, B. 3 cm; C, D. 1 cm; E–G. 5 mm.