Coleus kaminaensis Meerts & A. J. Paton, 2024

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 kaminaensis Meerts & A. J. Paton sp. nov.

Fig. 6 A – F

Type.

DR. Congo, Kamina, la Lovoi , Apr 1932, P. Quarré 2999 (holotype BR [ BR 0000017712682 ], [ BR 0000017712699 ], [ BR 0000017712750 ], [ BR 0000017712767 ]; isotype K) .

Diagnosis.

Related to C. gracilipedicellatus , on account of habit, profusely branched paniculate inflorescence, filiform pedicels jointed near apex and rachis distally zigzagging, differing in the anther not forming a pouch. It is also related to C. bifidus , on account of inflorescence architecture and anther structure, differing in the shallowly lobed style and the subentire leaf margin. The calyx of C. kaminaensis also differs by having the upper calyx lobe narrower and subulate at apex rather than clearly triangular in shape.

Description.

Perennial herb, 1.75–2.25 m high, with a horizontal rootstock (fide Quarré, not observed). Stem erect, thick, woody at base, rounded, slightly striate, pale brownish to purplish, lenticellate, subglabrous to thinly appressed puberulous, with short appressed antrorse hairs in the inflorescence, branching in upper half. Leaves opposite, ascending, subsessile, blade elliptic to ovate-elliptic, 4–8.5 × 1–2 cm, base cuneate to shortly attenuate, apex acute, margin shallowly and remotely crenate, to subentire, recurved, 4–5 pairs of secondary veins, shortly appressed pubescent on veins beneath, with red sessile glands, puberulous on upper surface; petiole 0–0.1 cm. Inflorescence paniculiform, lax, ca. 30 × 20 cm, much branched, flowers solitary in the axil of a small bract, more or less spirally or distichously arranged, occasionally 2 pedicels opposite at a node; inflorescence axis slender and slightly zigzagging at apex, puberulous, bracts narrowly ovate to linear, acute, ca. 1–1.5 mm long, caducous; pedicels 5–25 mm long, filiform, faintly jointed near tip, glabrous below joint, shortly pubescent as calyx above; calyx ca. 5 mm long at anthesis, shortly appressed pubescent and with orange-red sessile glands, tube campanulate ca. 2.5 mm long, faintly 10 - veined, lobes subulate, ca. 1.5–2 mm long, separated by broad truncate sinuses, with a short basal membrane; mature calyx not observed. Corolla blue (fide Quarré), ca. 9–11 mm long, tube almost straight, ca. 4–6 mm long, lower lip ca. 5 mm long, distally puberulous, curving upwards and closing throat, upper lip ca. 2 mm, upwardly pointing; stamens not exserted, filaments fused, anthers orbicular, not forming a pouch; style very shallowly lobed. Nutlets not observed.

Etymology.

Kamina, locality in DR. Congo where the type specimen was collected.

Distribution.

Endemic to SE DR. Congo, known only from the type specimen.

Habitat and ecology.

Savannah; ca. 1000 m elev.

Additional specimens.

None.

Notes.

1. Corolla structure, with lower lip upwardly curved, almost closing the throat and short stamens, suggest that the species is self-pollinating.

2. The single gathering of this species lacks fruiting calyces, with most flowers detaching at anthesis. Collecting notes indicate that the plant is heavily attacked by some leaf-eating parasite, virtually no leaves being untouched; this might account for the observed early abortion of flowers. The specimen is also galled. The species is said to be widespread in its locality.

3. Vernacular name: Lutoti na pori.

Figures

Figure 6. Coleus kaminaensis Meerts & A. J. Paton A stem and leaves B inflorescence C detail of inflorescence D flower E section of a corolla F fruiting calyx (P. Quarré 2999). Drawn by Hilde Orye. Scale bars: 1 cm (A, B); 2 mm (C); 1 mm (D, E, F).