Coleus conglomeratus (T. C. E. Fr.) Robyns & Lebrun

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 conglomeratus (T. C. E. Fr.) Robyns & Lebrun , Ann. Soc. Sci. Bruxelles, Sér. B 49: 105. 1929.

≡ Englerastrum conglomeratum T. C. E. Fr. , Notizbl. Bot. Gart. Berlin-Dahlem 9: 72. 1924.

≡ Plectranthus conglomeratus (T. C. E. Fr.) Hutch. & Dandy , Bull. Misc. Inform. Kew 1926: 481. 1926. Type: Togo, Sokode, Dec 1904, H. Kersting 93 (holotype B destroyed; isotype K [ K 000431858 ] fragment).

Description.

Shrub or perennial woody herb, up to 2 m high, almost leafless at flowering, rootstock with tubers. Stem erect, sparingly branching, rounded in the lower part, quadrangular upwards, striate, lenticellate, purplish, densely covered with ca. 4 mm-long patent stiff bristles and with very short appressed hairs, young growth beige tomentellose, with dense retrorse hairs and more sparse patent hairs, these turning into bristles in older growth. Leaves opposite, patent, petiole 0.5–1.0 cm (up to 5.0 cm outside Central Africa), blade ovate to ovate-elliptic, 1–3 × 1–2 cm (up to 16 × 8 cm outside Central Africa), apex acute to subobtuse, base cuneate and shortly attenuate into the petiole, margin crenate, upper surface puberulous and with pale sessile glands, lower surface shortly pubescent on veins and with pale sessile glands. Inflorescence in short lateral and terminal subsessile panicles, each comprising 3 to 5 branches 2–5 cm long; rachis densely covered with short glandular hairs, flowers solitary in the axil of a bract, helicoidally arranged on the rachis, distally often subopposite; bracts narrowly elliptic, ca. 1 mm long, pedicels ascending, with thin patent eglandular hairs, ca. 3 mm long, eccentrically inserted on calyx; calyx tubular, with dense short glandular hairs and pale sessile glands, 2 mm long at anthesis, ca. 4.5 mm in fruit, tube slightly curved, upper lobe broadly ovate to obovate, subobtuse, somewhat curving upwards, slightly decurrent, lobes of the lower lip narrowly triangular, 1–1.5 mm long, the median ones slightly longer; corolla ca. 6 mm long (up to 10 mm outside Central Africa), yellow inside, suffused with purple outside, with pale sessile glands, tube ca. 4 mm long, funnel-shaped, lower lip equalling the tube, upper lip shorter, with a broad emarginate median lobe and two smaller rounded lateral lobes, stamens with filaments free for most of their length, anthers golden; style golden, stigma bifid. Nutlets somewhat compressed, brown, shiny, red speckled, ca. 1 mm.

Distribution.

Togo, Benin, Sierra Leone, DR. Congo.

Habitat and ecology.

Savannah on lateritic crust; 100–500 m elev.

Additional specimens.

DR. Congo, Ubangi-Uele, Entre Businga et Banzyville [Mobayi-Mbongo], Jan 1931, J. Lebrun 2061 ( BR).

Notes.

1. New species record for DR. Congo.

2. The record in NW DR. Congo is remarkably disjunct, ca. 2000 km east of the nearest previously known locations in Togo. It had been misidentified in collections as C. tetragonus , on account of the bristles on the stem. It differs from the latter in the shorter pedicel (ca. 3 mm vs. 5–8 mm), shorter calyx (4.5 mm vs. 6–10 mm) and corolla suffused with purple.