Buchnera schaijesii Eb.Fisch., 2025

Fischer, Eberhard, 2025, Taxonomic novelties in Buchnera (Orobanchaceae) in Central and East Africa (Rwanda, Burundi, Democratic Republic of the Congo, Tanzania), Phytotaxa 704 (1), pp. 1-17 : 1-5

Buchnera schaijesii Eb.Fisch. sp. nov. ( Figs. 1–3 )

Type: — DEMOCRATIC REPUBLIC OF THE CONGO. Haut Katanga, Plateau Manika sur la piste Kolwezi-Musokantanda dans la première grande savane steppique située N & S de la piste, S10°45‘13‘‘ Es25°17‘19‘‘, 1480 m, 18 August 1990, M.Schaijes 4835 (holotype BR0000019400570!).

Diagnosis: — Buchnera schaijesii resembles B. henriquesii Engler (1893: 69) , but differs in the annual habit, the dense capitate spike, the linear bracts, and the light blueish-purple corolla with shorter tube with long white multicellular hairs on the tube and the smaller corolla lobes ( Tab. 1).

Description: —Annual erect herb, 7–10 cm tall, stems simple, branched from a base with an unbranched root 15 mm long, densely covered with white scabrid hairs of 0.1–0.2 mm length. Leaves sessile, opposite to alternate above, linear, hairy, 20–25 × 1–1.5 mm, only midvein visible, margin entire and flat. Inflorescence racemose, a dense, capitate spike, with four rows (orthostichae), quadrangular, the lowest flowers sometimes 2–3 mm apart from the rest of the inflorescence, up to 10 mm long, bracts linear, 5–6 × 0.6–0.7 mm. Flowers sessile, bracteoles linear, subulate, 3.4–3.8 × 0.8–1 mm; calyx narrowly tubular, 5–9 mm long, densely covered with white multicellular hairs, inflated in fruit, up to 12–14 mm long, with 5 teeth, longer teeth acute, narrowly ovate-triangular, 0.9–1.4 (2.1) mm long, small tooth 0.39–0.56 mm long.; corolla light blueish-purple, with cylindrical tube 6.5–7.2 × 0.6 mm, densely covered with white hairs outside up to 0.22 mm long, lobes 5, spathulate to obovate-elliptic, slightly emarginate at apex, 2.5–2.9 × (0.9) 1.15–1.7 mm, subglabrous outside and inside; stamens, acute, filaments of the longer pair 1 mm long, filaments of the shorter pair 0.5 mm long, with 1–1.1 mm long anther. Capsule 8–9 mm long, oblong. Seeds not observed.

Additional specimens seen (Paratype):— DEMOCRATIC REPUBLIC OF THE CONGO. Haut Katanga, Shabara, Sud 10°43‘39‘‘ Est 25°52‘51‘‘ dans la pieraille de la partie supérieure de la colline, 17 Mai 1990, M.Schaijes 4769 (BR0000019036076).

Distribution: — Democratic Republic of the Congo, only known from two localities in Haut Katanga.

Habitat: —Savanna 1425–1480 m altitude

Etymology: —The species name refers to Michel Schaijes, one of the most productive plant collectors in Haut-Katanga who discovered many species new to science.

Conservation status: — Buchnera schaijesii is only known from two collections in Haut-Katanga made in 1990. As the location is outside a protected area, the species is preliminarily assessed as Critically Endangered (CR).

Figures

FIGURE 1. Buchnera schaijesii.—A, habit.—B, inflorescence.—Photos by Michel Schaijes (©; Democratic Republic of the Congo, A: 90N-018 n°07, Shabara, Schaijes 4769; B: 90N-018 n°08, Shabara, Schaijes 4769).

FIGURE 2. Buchnera schaijesii.—Schaijes 4835 (BR). Reproduced with permission. © Botanical Garden Meise. https://www. botanicalcollections.be/specimen/BR0000019400570

FIGURE 3. Buchnera schajesii.—A. habit.—B–C. inflorescence.—D. bract.—E. calyx with bracteole.—F. apex of calyx.—G–H. calyx and corolla.—Drawn from the holotype by Eberhard Fischer.