Streptocarpus malaissei Eb.Fisch. & I.Darbysh., 2021

Fischer, Eberhard & Darbyshire, Iain, 2021, Five new species of Streptocarpus (Gesneriaceae) from Katanga, D. R. Congo, Plant Ecology and Evolution 154 (2), pp. 264-280 : 271

Streptocarpus malaissei Eb.Fisch. & I.Darbysh. , sp. nov.

( figs 5 , 9B ) –

Type: D.R. CONGO – Haut Katanga • Lubumbashi, voyage Lubudi ; 2 Jan. 1983; Bodenghien 30; holotype: BR [ BR0000016803442 ].

Diagnosis – The species differs from Streptocarpus michelmorei in the smaller pale lilac corolla lacking a deep violet patch on the palate and behind, the corolla tube being almost straight and not deepened on the lower side at the middle, and the upper and the lower lips being almost equal while in S. michelmorei the lower lip is distinctly larger. It also differs from S. michelmorei in the distinctly shorter capsule. The species differs from Streptocarpus solenanthus in the straight and usually shorter corolla tube and the shorter lower lip of the corolla. It differs from the morphologically similar Streptocarpus bampsii in the deep violet corolla with pale violet tube, shorter ovary and style and the shorter capsule.

Description – Monocarpic acaulescent herb. Unifoliate, lamina broadly ovate to nearly orbicular, 6–27 × 4–20 cm, base shallowly cordate, margin crenate-dentate, apex obtuse, usually withered, pubescent on upper and lower surface, with 12–17 pairs of lateral nerves, petiolode not exceeding 1 cm long, pubescent. Inflorescences 1–2 per plant, arising from the petiolode, peduncle up to 4–14 cm long, pubescent. Pedicels 5–9 mm long, eglandular pubescent, bracts linearlanceolate, up to 5 mm long. Calyx divided to base, lobes lanceolate, ± 4 mm long, hairs on calyx eglandular. Corolla pale violet to blue-mauve with tube pale violet, 15–30 mm long, densely eglandular-pubescent, glabrous within, tube straight, not or only slightly expanded towards mouth, 15–24 mm long, 3–4 mm in diameter, 5(–6) mm towards mouth, limb bilabiate, upper lip 3–7 × 3–5 mm, of two rounded lobes, lower lip 3–8 × 3–7 mm, of 3 rounded lobes, lateral lobe 3–5 × 3–6 mm, median lobe 3–8 × 3–7 mm. Stamens inserted in upper third of corolla tube towards mouth, filaments 7 mm long, glabrous, anthers white, 2 mm long, staminodes inserted below stamens, 0.8 mm long. Ovary densely eglandular-pubescent, ovary and style 7–15 mm long. Capsules 40–50 × 1–1.5 mm, eglandular-pubescent.

Distribution – Endemic to south-eastern D.R. Congo (Haut Katanga).

Habitat – Epiphyte or lithophyte on humid rocks in gallery forest or ravine near waterfall, 1450 m elevation.

Etymology – Named after François Malaisse, who made major contributions to the knowledge of the flora of Katanga, and who collected the type.

IUCN conservation assessment (preliminary) – Endangered: EN B1+2ab(iii). Streptocarpus malaissei is only known from 5 herbarium collections and 3 localities. The estimated AOO is 12 km 2 (assuming a 4 km 2 grid cell size). The habitat of gallery forest is under potential threat of logging. The most recent collection dates back to 1986. Thus, a preliminary assessment of Endangered: EN B1+2ab(iii) is proposed.

Additional specimens studied – D.R. CONGO – Haut Katanga • Lubudi, colline Kaboyaboya, rocher entre grotte; 1 Jan. 1983; Bodenghien 28; BR[BR0000016803459] • Biano, descente vers Mukabe Kasasi, riv. Lubudi, termitière; 2 Jan. 1983; Bodenghien 29; BR[BR0000016803473] • Lubudi, Chutes Dipera, Rive droite, Bas chute, epiphyte; 30 Dec. 1982; Bodenghien 18; BR[BR0000016803466] • Plateau des Biano, rivière Mulamba (chutes), dans les rochers (parfois suintantes); env. 1450 m; 6 Mar. 1986; Malaisse 13793; BR[BR0000016803435].

Figures

Figure 5 – Streptocarpus malaissei. A–B. Habit. C. Detail of inflorescence. D–E. Corolla. F. Corolla dissected showing position of stamens and staminodes. G. Stamens. H–I. Staminodes. K. Apex of ovary with style and stigma. L. Hairs on ovary. M. Young capsule. N. Mature capsule. A, C, D, F–N from Bodenghien 30, B from Malaisse 13795, and E from Bodenghien 18. Illustration by Eberhard Fischer.

Figure 9 – A. Distribution map of Streptocarpus malachiticola, S. bampsii, and S. salesianorum. B. Distribution map of S. schaijesii and S. malaissei. Map created using ArcMap 10.8 (https://www. arcgis.com). © Esri and its licensors, all rights reserved.