Thunbergia petersiana Lindau

Acanthaceae (part 1), Kaj Vollesen, Flora of Tropical East Africa, 2008

Morphology General Habit

Erect or straggling perennial or shrubby herb from creeping rootstock and fleshy roots; stems to 1.5 m long, quadrangular, glabrous to puberulous, with or without conspicuous bands of glossy setose hairs at nodes.

Morphology Leaves

Leaves thin, glossy, palmately veined; petiole (0.5–)1–13 cm long on vegetative leaves, glabrous to puberulous, distinctly ciliate or not; lamina ovate to cordiform or broadly so, largest (5–)6.5–17 × (3–)4.5–10 cm, apex acute to acuminate (rarely obtuse), apiculate, base subcordate to deeply cordate with rounded, hastate or sagittate lobes (rarely truncate), margin entire to grossly and irregularly dentate, glabrous to puberulous, often only on veins, rarely with longer glossy setose hairs.

Morphology Reproductive morphology Flowers

Flowers solitary (rarely paired) or from lower axils in racemes with small ovate sessile bracts; pedicels 1.5–5(–10 in fruit) cm long in solitary flowers and 0.5–2(–5 in fruit) cm in racemes, glabrous to puberulous (rarely with a few long glossy glandular hairs); bracteoles green, with conspicuous raised dark green reticulation, ovate-oblong, 0.9–2.2 × 0.4–1.2 cm, acute, with sparse to dense long (to 1.5 mm) glossy glandular hairs on veins and margins.

Morphology Reproductive morphology Flowers Calyx

Calyx glabrous or minutely puberulous, 1–2(–5 in fruit) mm high of which the broadly triangular lobes about half.

Morphology Reproductive morphology Flowers Corolla

Corolla limb and upper part of tube dark bluish purple or royal blue, lower part of tube white, throat yellow; tube (3.2–)3.5–5 cm long; lobes 1–1.8 × 1.5–2.5 cm.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 9–13 mm long, glabrous; anthers 2–2.5 mm long.

Morphology Reproductive morphology Flowers Gynoecium Style

Style with scattered glands.

Morphology Reproductive morphology Fruits

Capsule 8–13 mm in diameter, beak 13–18 mm, long.

Morphology Reproductive morphology Seeds

Seed dark reddish brown, ± 5 mm in diameter, reticulate to spinulose near apex.

Distribution

Range: Uganda. Range: Tanzania. Range: Kenya. Range: Sudan, Congo-Kinshasa, Burundi, Zambia, Malawi, Mozambique, Zimbabwe Flora districts: U2 U4 K1 K4 K7 T3 T4 T6 T7 T8 Range: Sudan, Congo-Kinshasa, Burundi, Zambia, Malawi, Mozambique, Zimbabwe

Ecology

Lowland evergreen forest, often in clearings or on edges, riverine forest, in S and W Tanzania in montane forest; 600–1550(–2200) m

Note

They differ from T. natalensis in being completely glabrous. The only totally glabrous form of T. natalensis has a white corolla. Some collections from K 4 have petioles only 0.5–1 cm long.

J. R. Timberlake, E. S. Martins (2013). Flora Zambesiaca, Vol 8 (5) Acanthaceae Part 1. Royal Botanic Gardens, Kew

Type

Mozambique, Boror, Peters s.n. (B† holotype). Neotype: Mozambique, Murrupula Dist., Cabo Mucaze, 15.i.1961, de Carvalho 442 (K neotype, BR), selected here.

Morphology General Habit

Erect or straggling perennial herb with several stems from a creeping rootstock; stems to 1 m long, quadrangular, glabrous to puberulous (rarely densely so), sometimes with long glossy setose hairs and conspicuous bands of glossy setose hairs at nodes

Morphology Leaves

Leaves glossy, palmately veined, glabrous to densely puberulous, densest on veins, often with longer glossy setose hairs on veins; petiole 2–14 cm long; lamina ovate to cordiform, largest 5–16 × 2.8–10.5 cm, widest point usually basal lobes or large teeth immediately above; apex acute to acuminate, rarely obtuse, apiculate, base subcordate to deeply cordate with rounded to hastate lobes; margin entire or with up to 3 large teeth per side

Morphology Reproductive morphology Flowers

Flowers solitary, rarely paired, or from lower axils in racemes with small ovate sessile bracts; pedicels 1–4 cm long, glabrous to sparsely puberulous; bracteoles pale green, with conspicuous raised dark green reticulation, 1.3–2.6(3.5) × 0.4–1 cm, lanceolate- oblong or ovate, acute, with sparse to dense long (to 2 mm) glossy glandular hairs on veins and margins

Morphology Reproductive morphology Flowers Calyx

Calyx minutely puberulous, 1–3(4 in fruit) mm long, the broadly triangular lobes about half

Morphology Reproductive morphology Flowers Corolla

Corolla limb and upper part of tube deep royal blue or deep purple, rarely white or pale blue, lower part of tube white, throat yellow; tube (2)3–4.8 cm long (over 4 cm if corolla white); lobes 1–2 × 1.5–2.5 cm

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 8–11 mm long, glabrous; anthers 2–2.5 mm long; style glabrous or with scattered glands

Morphology Reproductive morphology Fruits

Capsule 8–10 mm wide, beak 13–18 mm long

Morphology Reproductive morphology Seeds

Seeds dark brown, c.5 mm in diameter, reticulate to spinulose near apex.

Distribution

Zambia, Zimbabwe,Mozambique, Malawi. Also in Sudan, Congo, Burundi, Uganda, Kenya and Tanzania.

Ecology

In lower altitude forest, often in clearings or at edges, riverine forest, damp gullies in woodland, rarely in montane forest or montane grassland; 100–1500(1750) m.

Conservation

Widespread; not threatened.