Coleus congestus (R.Br.) A.J.Paton

Paton, A.J. et al (2019) Phytokeys 129: 36.

Can flower and fruit as a herb but frequently found as a shrub 1-1.5 m tall.

Stems 4-angled. Leaf blades about 2-8 x 1.5-6 cm, hairy on both the upper and lower surfaces. Numerous yellow, orange or honey-coloured glands present on the underside of the leaf blade and also the on petioles and twigs.

Flowers in +/- sessile dense clusters forming false spikes which are aggregated into panicles. Calyx about 1-2 mm long, outer surface clothed in tortuous erect hairs and orange coloured glands. Corolla about 4-11 mm long, outer surface clothed in white hairs and globular orange glands. Ovary appearing almost apocarpous but actually 4-lobed with the style in the centre. Nectary higher than the ovary but resembling each ovary lobe. Ovules four, one in each lobe.

Calyx persistent, about 2-3 mm long, clothed in hairs and reddish or orange glands. Nutlets rounded, flattened, about 0.8 mm diam. Seeds less than 1 mm long, flattened and curved +/- reniform. Cotyledons +/- orbicular, much broader than the radicle.

Cotyledons very broadly obovate to obtriangular, each +/- shaped like a butterfly wing, about 3 x 5 mm, upper and lower surfaces clothed in short hairs. First leaf blades +/- orbicular, upper and lower surfaces clothed in pale hairs, lower surface also sprinkled with orbicular glands. At the tenth leaf stage: leaf blade ovate to elliptic, apex bluntly pointed, base cuneate to obtuse, margin crenate with 8-11 blunt teeth on each side. Upper surface of the leaf blade bullate and the midrib depressed on the upper surface. Both the upper and lower surfaces, stems and petioles densely clothed in long pale or translucent hairs. Lower surface of the leaf blade heavily sprinkled with small, orbicular, orange-coloured glands. Leaf blade very aromatic when crushed. Glandular hairs present on the underside of the leaf blade, also present on the upper surface but much less common. Seed germination time 95 days.

Occurs in WA, CYP, NEQ and CEQ. Altitudinal range from 200-800 m. Usually grows in rocky areas in open forest but also found in similar situations in monsoon forest. Also occurs in Malesia (Timor, New Guinea and Louisiade Islands).

Leaves and branches crushed in water and drunk for internal complaints by the aborigines (Webb 1948).

Plectranthus congestus R.Br., Prodromus Florae Novae Hollandiae : 506 (1810). Type: [given by S.T.Blake, Contr. Queensland Herb. 9 (1971) 52 as Queensland, Endeavour River, Banks & Solander (BM, photo BRI).].