Coleus frederici G. Taylor

Meerts, Pierre J. & Paton, Alan J., 2024, The genus Coleus (Lamiaceae) in Central Africa (Democratic Republic of the Congo, Rwanda, Burundi), with the description of 15 new species, PhytoKeys 246, pp. 71-178 : 71-178

Coleus frederici G. Taylor , J. Bot. 69 (suppl. 2): 159. 1931.

≡ Neomuellera welwitschii Briq. , Bot. Jahrb. Syst. 19: 180. 1894., non Coleus welwitschii Briq.

≡ Plectranthus welwitschii (Briq.) Codd , Fl. Pl. Africa 42: t. 1646. 1972. Type: Angola, Pungo Andongo, 14 Apr 1857, F. Welwitsch 5544 (holotype BM; isotype C, K, LISU, MEL, PRE).

Description.

Short-lived perennial (annual or biennial after Hiern [1900]) herb, not aromatic (after Hiern [1900]), 0.60–1.20 m high. Stem erect, quadrangular, more or less crassulescent, puberulent, with very short retrorse hairs and sparse longer patent hairs and red sessile glands, branched. Leaves opposite, spreading, petiolate; blade ovate, 4.0–10.0 × 3.0–6.0 cm (up to 22 × 18 cm in Angola), base cordate to broadly rounded and shortly attenuate into the petiole, apex subacute, margin flat, crenate, teeth unequal in depth and breadth, with both sides subequal, the largest ones up to 5 mm deep; upper surface subglabrous, lower surface papillate on veins, rarely pubescent and with dense red sessile glands, ca. 5 secondary veins on either side; petiole 1.0– 3.5 cm (up to 18 cm in Angola), pubescent as stem. Inflorescence lax, 10–21 (– 30) cm long, with 6–13 verticils spaced 15–20 mm, cymes on a 5–15 mm long peduncle, dichasial, with two subequal opposite divergent cincinni with 1 median flower, cincinni ca. 5–12 mm long, (3 –) 5 - flowered, bracts ovate, ca. 3 mm long, early deciduous, pedicel 3–4 mm long, inserted eccentrically on calyx behind upper lobe. Flower: calyx ca. 2.5 mm long at anthesis, subglabrous, with red sessile glands, upper lip ovate, acute, ca. 1.4 mm long, upright, lower lobes much shorter, narrowly triangular, calyx at fruiting (in Angolan materials) more or less urceolate, contracted at throat, lobes parallel; corolla white or blue, with red sessile glands, ca. 18 mm long, tube sigmoid, with a narrow parallel-sided lower part ca. 4–5 mm long and a broader progressively dilated part ca. 5 mm long, lower lip ca. 9 mm long, cucullate, 5 mm deep, stamens fused, slightly exserted, anther 0.9 mm long; style undivided. Nutlets not observed (obovoid, slightly compressed, smooth, yellowish, in Angolan materials).

Distribution.

Angola, DR. Congo.

Habitat and ecology.

Shady places, scrub, forest fringe; 600–1100 m elev.

Additional specimens.

DR. Congo, Kasaï, Kwango, Tambu [Tambo], près du village, 14 Apr 1953, H. Callens 1173 ( BR); Haut-Katanga, Kundelungu, premier gué sur rivière Kalunda, entre Katwe et Lofoï, 19 May 1984, A. Bodenghien 139 ( BR).

Notes.

1. New species record for DR. Congo.

2. The materials collected in DR. Congo are at an early stage of flowering; however, the diagnostic character of calyx contracted at throat after anthesis is conspicuous in a few flowers in H. Callens 1173.

3. The specimen A. Bodenghien 139 (BR), collected ca. 1000 km east of previously known localities, is unusual in having lower leaf surface pubescent on veins.