Renealmia timmiorum Eb.Fisch., Killmann & Dhetchuvi, 2023

Fischer, Eberhard, Killmann, Dorothee & Dhetchuvi, Jean-Baptiste M. M., 2023, The family Zingiberaceae in Rwanda with description of two new species of Renealmia, Plant Ecology and Evolution 156 (2), pp. 225-238 : 225

publication ID	https://dx.doi.org/10.5091/plecevo.99146
persistent identifier	https://treatment.plazi.org/id/E5C393AC-620F-5C81-B1F6-2B1C4AFC84C9
treatment provided by	by Pensoft
scientific name	Renealmia timmiorum Eb.Fisch., Killmann & Dhetchuvi
status	sp. nov.

Treatment

Renealmia timmiorum Eb.Fisch., Killmann & Dhetchuvi View in CoL sp. nov.

Figs 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9

Renealmia congolana auct. non De Wild. & T.Durand: Champluvier (1988: 498), pro parte.

Type.

RWANDA - Western Province • Nyungwe National Park , crête au Sud-Ouest du Kamiranzovu; 02°28 ’27.11” S, 29°07 ’36.31” E; 2003 m; 5 Aug. 1976; Troupin 15842; holotype: BR [BR0000020217891] GoogleMaps .

Diagnosis.

The new species resembles Renealmia cincinnata and R. cabrae in the lax inflorescence but differs in the hyaline bracts, the elliptic lamina that is decurrent on the petiole, the pubescent and much shorter inflorescence with partial inflorescences (cincinni) bearing 1-3 flowers, and the fruits with 2-3 seeds per locule.

Description.

Perennial herb usually with few single shoots closely adjacent. Leafy shoots 40 to 100 cm tall, covered at base with imbricate leafless sheaths, the upper sheath sometimes with a reduced lamina. Leaves with sulcate sheaths surrounding the stem, with reticulately anastomosing venation and densely pubescent between the reticulations, with numerous simple and bifid hairs, margin membranaceous, reddish. Ligule very short, up to 2 mm long. Petiole 3-7 cm long, with reticulation and hairs within the furrows. Lamina elliptic, distinctly and progressively attenuate at base and decurrent at apex of petiole, acuminate to acute at apex, 19-25 cm long and 3.5-4 cm wide, median vein reticulate and glabrous, dark green at upper surface, greyish-green at lower surface, lateral veins visible only at lower surface, acumen at apex about 1 cm long. Inflorescence thyrsic, arising at base of leafy shoots, 14-25 cm long, entirely pubescent, with flowers and fruits horizontally arranged or bent upwards, in spiral arrangement. Peduncle about 10-20 cm long, up to 7 internodes reaching 8.5 cm of length, longer than the sheaths, with basal leafless sheaths short and dense, upper sheaths longer, of about 7 cm length, with bifid and caducous hairs at outer surface; rachis 5-10 cm long, entirely purple, with minute simple and caducous hairs, glabrescent. Bracts coriaceous to membranaceous, persistent, lanceolate, basal bract 2.5-3 cm long, the upper bracts shorter, glabrous with membranaceous ciliate margin, bracts of secondary axes lanceolate, with membranaceous ciliate margin, 1-2 cm long. Bracteoles tubular, with short abaxial slit, membranaceous, about 6-8 mm long, glabrescent. Partial inflorescences (cincinni) subsessile, with 1 to 3 flowers; peduncle about 2 mm long. Pedicels purple, becoming orange in fruit, glabrescent, about 5-20 mm long. Calyx persistent, accrescent in fruit, tubular, apex with acuminate lobes, glabrous except for ciliate margin, purple, about 6 mm, 1 cm long in fruit. Corolla white with purplish to violaceous marks; dorsal lobe rounded, 4.5-5 mm long, tinged with mauve; lateral lobes purplish, 4.5-5.1 mm long; labellum white with purple; claw 3.8 mm long; limb 6.3 × 7 mm, obtusely 3-lobed, mid-lobe deeply emarginate. Stamen with 1 bilocular theca, about 3.8 × 2 mm; lateral staminodes acuminate, ovate-lanceolate, 1 mm long. Ovary 2-3 × 1-2 mm, glabrescent, greenish-yellowish tinged with purple; epigynous glands rectangular, 1 mm long; style 8 mm long; stigma bilobed. Fruits elliptic, glabrous, about 1.5 cm long and 5 mm wide, red-orange, shining black at maturity. Seeds red-orange, surrounded by a yellowish aril, 2-3 per locule.

Distribution.

Montane forests of western Rwanda (Fig. 9 View Figure 9 ).

Habitat.

The new species is found at the type locality in a montane rainforest with Pentadesma reyndersii , Newtonia buchananii , Carapa wohllebenii , Parinari excelsa , and Strombosia scheffleri dominant in the tree layer. Other abundant species in the shrub and herb layer are Mimulopsis arborescens , Alchornea hirtella , Blotiella bouxiniana , Cincinnobotrys speciosum , Selaginella lewalleana , Saintpauliopsis lebrunii , and Scadoxus multiflorus . Other habitats mentioned on the specimens studied include Parinari excelsa -forest, forest with Pentadesma lebrunii , and relict transition forest. It occurs from 1580 to 2003 m.

Etymology.

Dedicated to the family Timm from Germany for their generous financial support of taxonomic research.

Preliminary IUCN conservation assessment.

Using a 3 × 3 km2 grid cell size, the EOO is estimated at 41.3 km2 which falls within the limits for the Vulnerable category; the AOO is estimated at 27 km2 which falls within the limits for the Endangered category. As all locations are situated in a protected area (Nyungwe National Park), the species is assessed as Least Concern (LC).

Additional material examined.

RWANDA - Western Province • Nyungwe National Park, Ntendezi; 02°27 ’07.43” S, 29°03 ’27.43” E; 1580 m; Habiyaremye s.n.; BRLU, NHR • Rangiro ; 02°27 ’36.41” S, 29°10 ’51.50” E; Bridson 379; BR [BR0000020217877], K • Rangiro , forêt dense près pépinière de Rutabanzogera; 02°27 ’13.61” S, 29°11 ’44.52” E; 1967 m; 12 Jun. 1978; Raynal 20486; P [P00072226], WAG [WAG0364620] • Rangiro; 02°27 ’36.41” S, 29°10 ’51.50” E; Troupin 16051; BR [BR0000020217884] • Gisakura, near waterfalls; 02°25 ’51.95” S, 29°07 ’02.92” E; 1933 m; 19 Oct. 2004; Dhetchuvi & Fischer 1991; KOBL, NHR • ibid.; 10 Dec. 2018; Fischer 1125/2018; KOBL, NHR • Site Gisakura/Karamba; 6 Jul. 1999; Liengola IBL 406; GIS • Gisakura; 6 Jul. 1999; Liengola IBL 407; GIS • Foret de Nyungwe , village Gasumo, sous-bois de la forêt primaire de montagne; 02°31 ’00.09” S, 29°04 ’28.19” E; 1680 m; 6 Jul.1999; Liengola IBL 412; GIS • Cyangugu, commune de Kagano, forêt de Gisakura, forêt à Pentadesma reyndersii et Syzygium guineense ; 02°27 ’06.31” S, 29°06 ’46.86” E; 1966 m; 10 Apr. 2000; Ewango & Boniface 2247; BR [BR0000009718661] GoogleMaps .

Notes.

Renealmia montana sensu Dhetchuvi (1996) comprises R. timmiorum and another undescribed taxon from eastern D.R. Congo found at lower elevations (850-1000 m) that will be validated in a future paper.