Description: Openly branched herbs, subshrubs or shrubs. Suffrutescent, often somewhat succulent, never woody. Branches often procumbent, less often erect, and capable of rooting at the nodes. Surface of branches, leaves and flowers vary in indumentum between species, such as including non-glandular hairs, glandular hairs, and a variety of sessile glands, most distinctive of which are coloured (often dark orange) multicellular sessile glands. Some species form a distinctive tuber from the seedling stage.
Leaves opposite, margin usually distinguished by serrate or crenate teeth, often slightly recurved. If appearing glabrous, often bearing scattered minute appressed hairs and sessile glands.
Inflorescence terminal or in the upper leaf axils; flowers in compact cymose clusters. Pedicel attached asymmetrically to the base of the calyx, opposite the lower lip. Calyx 2-lipped; lower lip ± equally 4-lobed (composed of 2 lateral lobes and 1 adaxial median lobe pair), with lobes ± triangular, acute or acuminate; upper lip a single broad lobe not longer than the lower lip. Corolla 2-lipped, lower lip longer than upper lip (rarely subequal); tube variously bent to straight, longer than calyx, swollen at the base or produced into a spur on the upper side; lower lip entire; upper lip 3- or 4-lobed. Stamens 4, fertile; anthers ± circular, medifixed. Ovary deeply 4-lobed; style gynobasic; stigma 2-fid.
Fruiting calyx usually accrescent. Fruit a mericarp, spheroid to ovoid, black to brown.
Flowering: Typically between September and June; some species capable of cleistogamy.
Distribution and occurrence: World: 294 species, tropical Africa, tropical Asia and Japan, Australia, Papua New Guinea, New Zealand and many islands throughout the Pacific. Australia: at least 64 species, with another 4 species naturalized, mainland States; native and exotic species cultivated are cultivated in Australia, including Coleus scutellarioides sens. lat.
Text by Text by T.C. Wilson (April 2026).
Taxon concept:
Taxa not yet included in identification key
Coleus sp. Boonalla (T.C.Wilson 1227)
| | Key to the species | |
| 1 | Bracts of inflorescence not organised in an imbricate crown-like covering at the apex of the inflorescence; pleasantly aromatic when touched crushed, or non-aromatic; pedicels spreading to ascending; mature calyx glabrous in throat | 2 |
| Bracts of inflorescence organised in a conspicuous imbricate crown-like covering at the apex of the inflorescence; pedicels erect and more or less appressed to the inflorescence axis; mature calyx densely hairy in throat | 10 |
| 2 | Sessile multicellular coloured glands absent on leaves and stems; bracts persistent at least until the fruiting stage; upper calyx lobe ovate to narrow ovate, apex acute, extending well past the lower lobes; corolla white or very pale mauve, with deeper purple markings on upper (adaxial) lobes, and upper lobes fused together more than two thirds their length | Coleus amboinicus |
| Sessile multicellular coloured glands present at least on either leaves or stems (except C. cremnus and C. suaveolens); bracts soon caducous (in C. alloplectus, often persistent in flower, but not persistent in fruit); upper calyx lobe broadly ovate, apex apiculate or rounded, more or less equal in length to the lower lobes; corolla mauve, blue or sometimes white, colour darker on upper and lateral lobes, with distinctive white midvein along lateral lobes, and upper lobes fused together between half and two thirds their length
Back to 1 | 3 |
| 3 | Habit straggling, never fully erect; branches distinctively red, indumentum with long hairs (to 3 mm) and glandular hairs throughout; leaf lamina very broadly ovate to nearly cordate | Coleus caldericola |
| Habit various; branches variously coloured, indumentum with combination of long hairs (to 6 mm) and glandular hairs absent or only at nodes; leaf lamina rarely to broadly ovate, and never nearly cordate
Back to 2 | 4 |
| 4 | Leaves with a finely crenate margin; lamina narrow-ovate to ovate (length to breadth ratio 2.2–4.2); inflorescence bracts usually persistent in flower; stamens and style well-exserted by 1.5–4.5 mm beyond the lower corolla lip | Coleus alloplectus |
| Leaves with a crenate to more or less toothed margin; lamina usually ovate to broad-ovate (length to breadth ratio mostly 1–2); bracts soon caducous; stamens and style scarcely, if at all, exceeding the lower corolla lip
Back to 3 | 5 |
| 5 | Leaf margin with 10–23 pairs of teeth; lamina always densely hairy | 6 |
| Leaf margin with 4–9 pairs of teeth, if 10–12 pairs of teeth then leaves sparsely hairy
Back to 4 | 7 |
| 6 | Branches densely covered by both glandular (i.e., gland-tipped) hairs and more or less spreading multicellular non-glandular hairs; corolla tube strongly curved downwards | Coleus graveolens |
| Branches densely covered by only appressed and retrorse multicellular non-glandular hairs, with glandular hairs occasional; branches appressed and retrorse or branches more or less glabrous; corolla tube ± straight
Back to 5 | Coleus argentatus |
| 7 | Branches sparsely covered with strongly appressed antrorse multicellular hairs; stem and leaves appearing shiny; corolla tube ± straight | Coleus nitidus |
| Branches sparsely to densely covered by spreading to retrorse multicellular hairs; stem and leaves with dull surface; corolla tube weakly to strongly curved downwards
Back to 5 | 8 |
| 8 | Branches moderately to densely covered with long, more or less spreading multicellular nonglandular hairs, and lacking coloured multicellular sessile glands; often emitting a geranium-like scent when crushed | Coleus cremnus |
| Branches sparsely to densely covered with short, more or less appressed, retrorse hairs, and with coloured multicellular sessile glands present; if scented when crushed, lacking a geranium-like scent
Back to 7 | 9 |
| 9 | Coloured multicellular sessile glands absent (or occasional) on leaves and stem; branches densely covered with shortly, more or less appressed retrorse hairs; lamina densely hairy; corolla mauve with a tube strongly curved downwards; all parts emitting a strong scent akin to Lavender (Lavandula sp.) when touched or crushed | Coleus suaveolens |
| Coloured multicellular sessile glands present on leaves (at least densely distributed on lower surface) and usually stem; branches sparsely to densely covered with short retrorse hairs; lamina sparsely covered with antrorse hairs; corolla blue or mauve (sometimes nearly white), and a tube weakly curved downwards; emitting a pungent medicinal-like scent, usually strongly-scented around inflorescence
Back to 8 | Coleus australis |
| 10 | erect suffrutescent shrub to 3 m tall, more or less pleasantly aromatic when touched or crushed; leaves ovate, up to approximately 300 mm long, not succulent | Coleus barbatus |
| erect or spreading semi-succulent herb to 0.6 m tall, powerfully and unpleasantly aromatic when touched or crushed; leaves narrow or broadly ovate to obovate, approximately 50 mm long, succulent
Back to 1 | 11 |
| 11 | inflorescence with short internodes such that flowers and fruits densely clustered; corolla 8–10 mm long | Coleus caninus |
| inflorescence lax basally with at least 1 or 2 spaced fruiting verticils below the flowers; corolla at least 12 mm long
Back to 10 | 12 |
| 12 | Inflorescence elongate, 70–150 mm long with 5–12 spaced fruiting verticils below the flowers; corolla 12–20 mm long | Coleus neochilus |
| Inflorescence compact, usually 30–50 mm long with 1 or 2, rarely more, spaced fruiting verticils below the flowers; corolla 20–25 mm long
Back to 11 | Coleus comosus |
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