Buchnera kisimbai Eb.Fisch. & Ilunga, 2025

Buchnera kisimbai Eb.Fisch. & Ilunga sp. nov. ( Figs. 1–2 View FIGURE 1 View FIGURE 2 , 3A View FIGURE 3 , 4 View FIGURE 4 )

Type: — DEMOCRATIC REPUBLIC OF THE CONGO. Haut-Katanga, Fungurume Hill V, 10°37’28’’S 26°16’28’’, 1170 m, 6 April

1990, TROPMETEX: R.R. Brooks, A. Baker, H. Schat & F. Malaisse 150 ( holo-: BR0000018462845, iso-: MO, K, WAG, C, P, PE,

MPN, IBE, MBM).. Diagnosis: — Buchnera kisimbai resembles B. randii S. Moore (1900: 467) ( Figs. 3B, C View FIGURE 3 , 5–6 View FIGURE 5 View FIGURE 6 ) but differs in the ovate cauline leaves of 28.6 – 58 × (7.1) 18 – 30 mm (linear-lanceolate with (26) 28 – 54 ×1.4 – 4.5 (5.7) mm in B. randii ), the bracts smaller (3.9 – 5.15 × 2.3 – 2.9 mm vs. (2.5) 4.5 – 6 × 1.2 – 2 mm in B. randii ), the larger calyx of 4.5 – 5.9 × 0.8 – 0.95 mm (2.5 – 3 × 1.1 – 1.2 mm in B. randii ), the longer corolla tube (4.5 – 5.6 × 0.43 – 0.87 in B. randii ), and the larger corolla lobes of (2.7) 4.47 – 4.67 × 2.3 – 2.9 mm (1.25–1.57 × 1–1.18 mm in B. randii ) ( Tab. 1).

Description: —Annual erect herb, (14.3–)22.1–54.3(–74.3) cm tall, stems simple, branched from a base, densely covered with white scabrid hairs. Leaves sessile, opposite, the basal leaves forming a small rosette, often caducous, lamina narrowly oblong-elliptic to obovate, 29–31 × 18,6– 20 mm, obtuse at apex, densely covered with small papillose hairs below, cauline leaves with ovate lamina, 28.6 – 58 × (–7.1) 18 – 30 mm, acute at apex, hispid on both sides. Inflorescence racemose, a dense, capitate spike, with four ranges (orthostichae), 14–43 mm long, bracts ovate to narrowly ovate-elliptic, 3.9–5.15 × 2.3–2.9 mm, acute at apex, hispid at margin and on outer, abaxial side. Flowers sessile, bracteoles linear, subulate, 2–4 mm, margin hispid; calyx tubular, 4.5–5.9 mm long, hispid with white multicellular hairs on the veins, inflated in fruit, with 5 unequal teeth, longer teeth acute, narrowly ovate-triangular, 1.4 (–1.8) mm long, small tooth 0.9 – 1.1 mm long.; corolla light blueish-purple, with cylindrical straight tube 5.15–6.55 × 0.64 – 0.75 mm, densely covered with few white hairs outside, lobes 5, obovate to obovate-cuneiform, (2.5–) 4.47– 4.67 × 2.3 – 2.7 mm; stamens with 1.2–1.4 mm long anther, acute, filaments of the longer pair 1 mm long, filaments of the shorter pair 0.5 mm long. Capsule 3.5–4.5 mm, long, oblong, glabrous.

Distribution: —Endemic to the Copperbelt of D.R. Congo.

Habitat:—Savannas, rocky slopes on copper and cobalt-rich soil between an altitude of 1200 and 1505 m ( Fig. 7 View FIGURE 7 ).

Additional specimens seen ( Paratypes):—D.R. CONGO. Haut-Katanga. Fungurume (entre Likasi et Kolwezi), 16April 1975, H. Breyne2391 (BR0000018462708); Fungurume, 24April 1974, F.Malaisse 7733 (BR0000018462807); Chabara 30 May 1980, F.Malaisse10859 (BR0000018462791, BR0000018462784); Chabara, 30May 1980, F.Malaisse 10859Bis (BR0000018462777); Goma (Tenke), 4 April 1987, F. Malaisse 11793 (BR0000018462838); Kwatebala, 31 May 1980, F. Malaisse 10913 (BR0000018462814); Kwatebala, 3 July 1981, F. Malaisse 11846 (BR0000018462821); Kwatebala South, 20April 2008, F. Malaisse, G. Handjila & K. Kisimba 421 (BR0000022455772); Shadirandzoro East [1], 20April 2008, F. Malaisse, G. Handjila & K. Kisimba 443 (BR0000006757236); Parc National de l’Upemba, Vallée Lufira vers Katupile, Secteur Misubruzi, 18April 1959, J. de Wilde 734 (R0000018462715); Parc National de l’Upemba, Rive distr Malule N., Mont Mia près de Priamabwa, 28 February 1949, G.F. de Witte 5662 (BR0000018462722); Parc National de l’Upemba, Colline entre riv. Lukoka et riv. Muasi, 21 June 1949, G.F. de Witte 6833 (BR0000018462760); Parc National de l’Upemba, au N. de Mabwe, 7 March 1949, G.F. de Witte 5761 (BR0000018462739); Parc National de l’Upemba, Kiamakoto, 13 June 1949, G.F. de Witte 6548 (BR0000018462753); Parc National de l’Upemba, Forêt au N. de Mabwe, 22 May 1949, G.F. de Witte 6275 (BR0000018462746).

Etymology: —The species name refers to Emile Kisimba Kibuye, (born 30 March 1954, see Leteinturier & Malaisse 2001), one of the most productive field guides, who devoted his entire life to botanical prospecting. He accompanied François Malaisse 47 years long. He was an inspiring field botanist in the academic circle of the Katanga region.

Conservation status: — Buchnera kisimbai is only known from the above cited collections in Haut-Katanga and in the Upemba National Park. Growing in heavy metal-laden soils, this species is endangered by mining activities (e.g., copper and cobalt extraction), pending a proper extinction risk assessment, is here preliminary assessed as Vulnerable (VU).

Notes: — Mielcarek (1996) has recorded Buchnera randii sensu Mielcarek non S.Moore in Burundi, but the only collection ( Lewalle 4291, BR) represents B. decandollei Govaerts (1996: 14) . The locality Goma (Tenke), erroneously placed by Mielcarek (1996) in the phytogeographical district of « Lacs Édouard et Kivu » is situated in Haut-Katanga.