Vitex rivularis Gürke, 1903

Meerts, Pierre, 2018, Synopsis of the genus Vitex (Lamiaceae) in the Democratic Republic of the Congo, Plant Ecology and Evolution 151 (3), pp. 380-392 : 389

15. Vitex rivularis Gürke

( Gürke 1903: 297); Pieper (1928: 1956); Aubréville (1956: 233); Huber et al. (1963: 446); Moldenke (1968: 34); Lebrun & Stork (1997: 526).

– Type: Cameroun, Bipinde, am Lokundje-Ufer , 80 m, Apr. 1897, Zenker 1333 (holo-: B †, iso-: Pbarcodes P 00442317, P 00442318 & P 00442319, BM barcode BM 000834558, E barcodes E 00214021 & E 00193458, Gbarcodes G 00023655 & G 00023656, Wbarcode W 1898-0006745, HBG barcode HBG513570 , Kbarcode K 000192753, WU barcode WU 0069994, KFTA barcode KFTA 0002112 ) .

Vitex vermoesenii De Wild. ( De Wildeman 1929a: 16; 1929b: 66) pro parte, excl. syntypes Pynaert 1696 (BR, BM) , Sparano 129 (BR) , Vermoesen 1733 (BR) . – Type: D.R. Congo, Mayombe, Temvo , 6 Mar. 1919, Vermoesen 1742 (lecto-: BR barcode BR 0000008906588, designated here ; isolecto-: BR barcode BR 0000008906595, BM barcode BM 001209278), synon. nov .

A tree. Twigs almost glabrous except at nodes. Leaves 5–7-foliolate; petiole 10–20 cm, almostglabrous; petiolules 5–25 mm, lamina abruptly contracted into a long fine acumen, upper surface slightly scabrid, lower surface almost glabrous, with many yellow glands, (8–)11–20 pairs of secondary veins. Inflorescence of dichasia, much branched, long pedunculate, multiflorous; calyx 1.5–2 mm, with many yellow glands, corolla c. 4 mm, whitish, with lower lip purplish, ovary glandulose. Fruit 20–30 mm long.

Distribution – Wtropical Africa, from Ghana southwards to Angola.

Note – Lectotypification of Vitex vermoesenii De Wild. Five syntypes are cited in the protologue (de Briey 55, Pynaert 1696, Sparano 129, Vermoesen 1742, Vermoesen 1933). They are an admixture of two species. Pynaert 1696 (BR barcodes BR0000009861466 & BR0000009861794, BM barcode BM001209279), Sparano 129 (barcode BR0000009862159), and Vermoesen 1933 (barcodes BR0000009862180 & BR0000009861817) are Vitex ferruginea Schumach. & Thonn. On the other hand, de Briey 55 (BR barcodes BR0000009861480 & BR0000009862173) and Vermoesen 1742 (BR barcodes BR0000008906588 & BR0000008906595, BM barcode BM001209278) are Vitex rivularis Gürke. The protologue describes Vitex vermoesenii as having “… calice de env. 1 mm de long, …” and “… inflorescence formant une panicule terminale ample…” “… inflorescences partielles axillaires atteignant 10 cm de diam.; …” ( De Wildeman 1929a); all these characters clearly point to Vitex rivularis . Vermoesen 1742 (BR barcode BR0000008906588) is chosen as the lectotype because it has De Wildeman’s handwriting on the label.