Renealmia susannae-katziae 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/54570C64-D7F3-5D78-8B66-49DD44BF7216
treatment provided by	by Pensoft
scientific name	Renealmia susannae-katziae Eb.Fisch., Killmann & Dhetchuvi
status	sp. nov.

Treatment

Renealmia susannae-katziae Eb.Fisch., Killmann & Dhetchuvi sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 9 View Figure 9

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

Type.

BURUNDI - Bubanza Province • Mugomero (Rugazi); 03°13 ’33.65” S, 29°31 ’21.89” E; 2167 m; 2 May 1981; Reekmans 10045; holotype: BR [BR0000020218539] GoogleMaps .

Diagnosis.

The new species resembles Renealmia africana and R. dewevrei De Wild. & T.Durand. It differs, however, in the partial inflorescences (cincinni) with 1-2(-4) flowers (vs 1-7 in R. africana and 4-8 in R. dewevrei ), the glabrous calyx and fruit (vs pubescent in R. africana and R. dewevrei ), the subglobose capsules, and the 2-3 seeds per locule (vs 11-13 in R. africana and 9 in R. dewevrei ).

Description.

Perennial herb forming a dense clump. Leafy shoots 100 to 200 cm tall, covered at base with imbricate leafless sheaths. Leaves with sulcate sheaths surrounding the stem, with reticulately anastomosing venation and numerous brownish glands between the reticulations. Ligule obtuse, up to 2 mm long. Petiole 4-6(-10) cm long. Lamina narrowly obovate, attenuate at base and decurrent along petiole, caudate-acuminate at apex, about 60 cm long and 10 cm wide, greyish-green at lower surface, lateral veins visible at both surfaces. Inflorescence thyrsic, arising at base of leafy shoots, 20-40 cm long. Peduncle about 30 cm long, with up to 5 leafless glabrescent sheaths of about 5-10 cm length, ciliate near margin, internodes glabrous; rachis about 1/2 of inflorescence, glabrous, red. Bracts caducous, membranaceous, pubescent with persistent hairs, ciliate at margin, about 1 cm long. Bracteoles caducous, membranaceous, tubular, abaxially shortly incised, pubescent with persistent hairs, ciliate at margin, about 5 mm long. Partial inflorescences (cincinni) subsessile, with 1 to 2(-4) flowers. Pedicels red-orange, sparsely pubescent, with minute hairs, about 3-15 mm long, regularly enlarged at apex. 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 yellowish with purplish to violaceous marks; dorsal lobe rounded, 5 mm long, tinged with mauve; lateral lobes purplish 5 mm long; labellum yellowish with purple; claw 3.7 mm long; limb about 8 mm in diameter, the free portion 3-lobed. Stamen with 1 bilocular theca, about 2 mm long; lateral staminodes ovate, acuminate, 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, 0.7 × 1.1 mm. Fruits subglobose, glabrous, shining black at maturity, 10 × 5-8 mm. Seeds globose-polygonal to irregular, 3 mm in diameter, 2-3 per locule.

Distribution.

Only known from Nyungwe National Park, Rwanda, and western Burundi (Fig. 9 View Figure 9 ).

Habitat.

The new species grows close to a small stream with Carapa grandiflora , Tabernaemontana stapfiana , Lepidotrichilia volkensii , Alangium chinense , Myrianthus holstii in the tree layer, Scepocarpus hypselodendron and Illigera vespertilio as lianas, and Fagopyrum snowdenii , Uvariopsis congensis (juvenile), Ptisana africana , Blotiella bouxiniana , Impatiens erecticornis , Antrophyum mannianum , Culcasia falcifolia , and Polystachya cultriformis in the herb layer or as stem epiphytes. A specimen was collected near the road passing through Cyamudongo Forest to Nyakabuye in a forest with Newtonia buchananii , Entandrophragma excelsum , Myrianthus holstii , Polyscias fulva , Maesa latifolia , Neoboutonia macrocalyx , Xymalos monospora , Astropanax abyssinicus , and Tabernaemontana stapfiana in the tree layer. The species occurs from 1240 to 2267 m.

Etymology.

Dedicated to Mrs Susanne Katz on the occasion of her 50th birthday for her generous financial support of taxonomic research.

Preliminary IUCN conservation assessment.

Karuzi and Mabayi are now densely and heavily populated area. The location of Kihofi is likely lost due to a large sugarcane plantation and a factory which are installed there. The collecting sites in Burundi are located outside protected areas where the species’ habitat is rapidly degrading due to agriculture and urbanization expansion. By considering the loss of habitat, the number of locations is 4 or 5. Two are located within protected areas (Nyungwe National Park). Several adverse factors are affecting the extent and quality of habitat of this species like logging and agriculture. The calculated EOO is 6680 km2 and the AOO is 54 km2. Based on the above observations, it is assessed as Endangered: EN B1 ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v).

Additional material examined.

RWANDA - Western Province • Nyungwe National Park, Cyamudongo Forest, near Riv. Nyamabuye : 02°33 ’10.015” S, 28°59 ’31.46” E; 1755 m; 1 Apr. 2004 GoogleMaps ; Fischer 156/2004, KOBL, NHR • Cyamudongo Forest, along road to Nyakabuye ; 02°33 ’30” S, 28°59 ’01” E; 1978 m; 18 Oct. 2004 GoogleMaps ; Dhetchuvi & Fischer 1990; KOBL • ibid.; 10 Dec. 2018 GoogleMaps ; Fischer 1137/2018; KOBL • 23 km on road Pindura-frontiere Burundi ; 02°34 ’45.38” S, 29°12 ’13.35” E; 1720 m; 13 Aug. 1974 GoogleMaps ; Auquier 3742; BR [BR0000020218010].

BURUNDI - Bubanza Province • Bubanza; 19 Dec. 1970; Lewalle 5101; BR [BR0000014516139] • Bubanza, Mabayi, route vers Cibitoke; 02°42 ’36.15” S, 29°17 ’20.15” E; 2267 m; 22 Jun. 1969; Lewalle 3799; BR [BR0000020218003] • Bubanza, Muyebe, Rugazi; 03°12 ’54.72” S, 29°31 ’10.34” E; 1845 m; 16 Oct. 1974; Reekmans 3839; BR [BR0000020218591] • Bubanza, Cibitoke-Mabayi, vallee Nyamagana ; 2 Mar. 1969; Lewalle 3285; BR [BR0000020218607] GoogleMaps . - Rutana Province • Kiofi, Mosso ; 04°02'S, 30°07'E; 1240 m; 15 Mar. 1952; Michel & Reed 1371; BR [BR0000020218546] GoogleMaps . - Karuzi Province • Kitega, Chefferie Bweru , environs de Karuzi; 03°08 ’33.22” S, 30°05 ’38.16” E; 1758 m; 21 Jan. 1959; Van der Ben 2446; BR [BR0000020218027] GoogleMaps .