Coleus hereroensis (Engl.) A.J.Paton

J. R. Timberlake, E. S. Martins (2013). Flora Zambesiaca, Vol 8: part 8. Royal Botanic Gardens, Kew

Type

Type: Namibia, Hereroland, Kaiser Wilhelmsberg near Okahandja, v.1886, Marloth 1350 (B† holotype, G, M, PRE, SAM). Codd (1985) cites the original holotype as being destroyed in Berlin with a Kew specimen cited as the lectotype. However, there is no specimen bearing this number at Kew.

Morphology General Habit

Annual or short-lived perennial herb or herbaceous shrub 0.2–2 m tall, with a single stem arising from a fibrous root system; slightly aromatic- Stems erect, quadrangular, branching above, pubescent with short retrorse eglandular and sometimes spreading eglandular or glandular hairs and red sessile glands

Morphology Leaves

Leaves petiolate, spreading; blade 20–80(100) × 15–55(70) mm, ovate or triangular, sometimes folded along midrib on drying, crenate to deeply crenate or dentate, apex acute, base cuneate to cordate, attenuate at petiole, pubescent to almost glabrous with eglandular (sometimes glandular) hairs and reddish sessile glands

Morphology Reproductive morphology Inflorescences

Inflorescence lax to fairly condensed, with adjacent (10)15–50-flowered verticils touching distally or 10–25 mm apart, bract subtending opposite pedunculate (5)7–25-flowered cymes, first branch dichasial producing two lateral cincinni up to 20 mm long; peduncle 3–25 mm long; bract inconspicuous, 2–10 mm long, linear, persistent, sometimes withering by fruiting stage; pedicel 1–3 mm long

Morphology Reproductive morphology Flowers Calyx

Calyx 2 mm long, sometimes purplish above, pubescent with glandular or eglandular hairs and reddish sessile glands; fruiting calyx 5–7 mm long, erect, parallel to adjacent calyces, tubular, variably curved with throat sometimes at right-angles to tube, slightly constricted at throat, pedicel attached eccentrically behind posterior lip; throat truncate; lobes ± equal, lanceolate, variably hairy on inner surface, sometimes finally reflexed

Morphology Reproductive morphology Flowers Corolla

Corolla blue, 9–12 mm long, sparsely pubescent on lobes, with scattered red sessile glands; tube 4–7 mm long, sigmoid; posterior lip shorter than anterior; anterior lip 4–8 mm long, enclosing stamens or stamens finally exserted

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Staminal filaments fused at base or free

Morphology Reproductive morphology Fruits

Nutlets dark brown, shiny, smooth, 1 mm long, with inconspicuous reddish gland dots; producing speckled mucilage.

Distribution

Botswana, Zimbabwe. Also in Angola, Namibia and South Africa.

Ecology

On rock outcrops, rocky areas in woodland or grassland, streamsides or roadsides; 900–1800 m.

Conservation

Widespread: Least Concern.

Recognition

rather than the posterior being clearly broader, the calyx tube is slightly constricted at the calyx throat, and the fruiting calyx axis is usually parallel with that of the main inflorescence with the mouth directed upwards, rather than perpendicular to the main axis with the mouth directed down or away from the axis as in P. tenuicaulis. Within the Flora area two forms are apparent. One is from W and S Zimbabwe and N and SE Botswana and is similar to the types of P. matabelensis and P. matopensis with peduncles longer than 10 mm. These plants also differ from the type in being somewhat shorter (0.2–1 m high) with spreading hairs on the petioles and more deeply toothed leaves but, apart from peduncle length, none of these characters show a clear delimitation. Long peduncles are also occasionally found in specimens from E Zimbabwe; the type form with short peduncles also occurs in W and S Zimbabwe but not in Botswana. When material from Angola, Namibia and South Africa outside the Flora area is considered, all these character distributions break down. Hence, following Codd (1985) P. hereroensis is regarded as one variable species. Coleus aconitiflorus from Angola differs only in having lanceolate leaves and is here put into synonomy. Similar leaves are also seen in the type of C. polyanthus from the Matobo Hills. P. hereroensis differs from P. tenuicaulis in having the fruiting calyx teeth subequal