Vitex discoideoglandulosa De Wild., 1929

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 : 384-385

6. Vitex discoideoglandulosa De Wild.

( De Wildeman 1929a: 10).

– Type: D.R. Congo, Kasaï, entre Lubue et Bena-Makima, May 1910, Sapin s.n. (lecto-: BR barcode BR 0000018421408, designated here) .

Vitex guerkeana De Wild. ( De Wildeman 1909: 129) nom. illeg. non Vitex guerkeana Hiern.

Alianescent shrub. Twigs solid, not myrmecophilous, pubescent. Leaflets 5, petiolulate, lamina pubescent on both surfaces. Inflorescence of thyrses, grouped in a terminal panicle. Flowers whitish. Fruit globose, brownish, c. 5 mm, subtended by the patelliform calyx.

Distribution – Endemic to D.R. Congo.

Note – V. discoideoglandulosa is a member of the complex of V. thyrsiflora-V. buchananii , characterised by a thyrsoid inflorescence, more or less lianescent habit and small globose fruits (section Terminales W.Piep.). Pieper (1928) regarded it as a synonym of V. volkensii Gürke , an East African plant now synonymized with V. buchananii . However, V. discoideoglandulosa lacks the diagnostic trait of V. buchananii , i.e. the golden-yellow glandulose outer fruit layer exfoliating at maturity. It is undoubtedly a distinct species. Table 1 summarizes the differences between the three species.

Lectotypification of Vitex discoideoglandulosa De Wild. De Wildeman (1929a) cited six syntypes (Claessens s.n., Gillet 1973, Gillet s.n. (coll. 1901), Gillet s.n. (coll. 1902), Gillet s.n. (coll. 1926), Sapin s.n.), corresponding to six sheets in BR. The only specimen with fruits is selected as the lectotype, because the characters of the fruits are discriminant with respect to V. buchananii .