Erect shrubs, lianes or small trees; young branches red-brown with prominent corky lenticels. Leaves opposite or alternate, petiolate, coriaceous, ovate to narrowly elliptic to lanceolate, glabrous, margin recurved. Flowers bisexual, in 3(4)-flowered, almost sessile axillary clusters; pedicels slender. Calyx: receptacle tube funnel-shaped, not contracted above ovary; calyx lobes 5 or 6, ovate-oblong. Petals minute, scale-like, arising at throat of receptacle between filaments. Stamens twice as many as sepals, alternately long and short, in a single series at mouth of receptacle tube; filaments slender, decurrent down receptacle tube; anthers oblong. Disc cup-shaped, lobed. Ovary 1-locular, sessile; style filiform; stigma capitate. Fruit drupaceous with sclerified pericarp, inside persistent receptacle tube. Seed without endosperm; cotyledons thick.
Species 9, trop. Africa; sthn trop. Afr. 2, Angola, Zambia.
Small trees or shrubs. Leaves petiolate, entire, elliptic to oblong-elliptic, broadly acuminate, cuneate at base, glabrous or slightly pubescent on midrib. Flowers small, in axillary fascicles; pedicels longer than flowers. Calyx +/- half as long as corolla, with 5 spreading, broadly triangular lobes, scarcely accrescent. Corolla cylindric, tomentellous outside above calyx; lobes 5, half as long as tube, +/- reflexed or spreading. Stamens included, arising above middle of corolla tube; filaments short, filiform; anthers opening by longitudinal slits. Style short, included. Fruit a globose berry 6-8 mm in diameter.
Perennial, aromatic (sometimes nauseatingly so), glabrous herbs. Leaves alternate, pinnately divided, spotted with glands. Sepals 4, lanceolate. Petals 4, in central flower 5, hooded, dark yellow, margin toothed or hairy. Stamens 8-10. Styles fused. Fruit a 4- or 5-celled capsule.
Recorded as occasional garden escapes, e.g. *Ruta chalepensis L. in Angola.
Biennial or perennial herbs or rarely small shrubs. Leaves alternate or sometimes predominantly basal, simple, variously dentate to subentire. Flowers irregular, in terminal, bracteate, racemes. Calyx 5-lobed; lobes equal to subequal, shorter than corolla tube. Corolla tubular, cylindrical or inflated-globose, usually constricted towards base; limb usually bilabiate with lips spreading or erect, upper lip shorter. Stamens 4. Capsule conical to ovoid, septicidal. Seeds small, many.
Species +/- 20, Europe, Mediterranean and Canary Islands; naturalised elsewhere in the world, as an escape from cultivation; sthn trop. Afr. 1: *Digitalis purpurea L. recorded from Zimbabwe and Malawi.
Erect perennial herbs with simple or sparsely branched, glabrous, quadrangular stems. Leaves opposite, shortly petiolate, ovate to lanceolate, acuminate at apex, serrulate except cuneate base, scabrid above, penninerved. Inflorescence a lax raceme with a pair of flowers at each floriferous node. Flowers 2-lipped, reddish purple with paler throat. Calyx glabrous, 5-lobed; lobes ovate to lanceolate. Corolla slightly irregular; upper lip 2-lobed, with glandular hairs inside; lower lip 3-lobed; tube gradually widening, much longer than lobes. Stamens 4; filaments of anterior stamens geniculate and incurved, papillate and with glandular hairs, filaments of posterior stamens +/- straight, much shorter; anthers with 2 equal thecae. Ovary globose, glabrous; style filiform; stigma 2-lobed. Fruit a septicidal capsule. Seeds with alveolate endosperm.
Species 4, Old World tropics; sthn trop. Afr. 1: Artanema longifolium (L.) Vatke, Angola.
Trees; branches terete, striate. Leaves alternate, sessile, lanceolate, acuminate, base cuneate; stipules absent. Flowers bisexual or unisexual (dioecious), in fascicles on old wood or on branches, often subtended by spirally arranged bracts. Calyx a single whorl of 5 free, quincuncial sepals. Corolla broadly tubular; tube shorter than the 5 broadly ovate lobes. Stamens +/- 20 in a single whorl, +/- 3 opposite each corolla lobe and arising at top of corolla tube; filaments well-developed, glabrous; anthers extrorse, glabrous, absent in female flowers; staminodes 5 or more, much shorter than corolla lobes, usually petaloid, fimbriate, glabrous, often inflexed and covering ovary. Disc absent. Ovary many-locular; placentation axile; style usually included. Fruit usually depressed-globose; several- to many-seeded; outer pericarp often woody. Seeds strongly laterally compressed; testa smooth, shining; scar adaxial, nearly full-length, very narrow; embryo with thin foliaceous cotyledons and exserted radicle; endosperm copious.
Species +/- 6, W and WC trop. Africa; sthn trop. Afr. 1: Omphalocarpum mayumbense Greves, Angola (Cabinda).
Trees. Leaves spirally arranged; stipules absent. Flowers bisexual, solitary or in few-flowered fascicles, axillary or in axils of fallen leaves. Calyx a single whorl of 5 free imbricate sepals. Corolla cyathiform; lobes 5, free almost to base, simple, imbricate, spreading or reflexed at tip. Stamens 10-15, 2 or 3 opposite each corolla lobe, arising ?-1/2-way up on corolla lobes; filaments of each pair or group of 3 fused almost to apex, hairy; anthers extrorse, hairy or glabrous; staminodes 5, usually 3-dentate at apex, hairy. Disc absent. Ovary 10-locular; placentation axile; style slightly exserted. Fruit subglobose, several-seeded. Seed strongly laterally compressed; testa smooth, shiny; scar adaxial, almost full length, very narrow; embryo with thin foliaceous cotyledons and exserted radicle; endosperm present.
Species 2, W trop. Africa; sthn trop. Afr. 1: Tridesmostemon omphalocarpoides Engl., Angola (Cabinda).
Perennial herbs, sometimes shrubby, erect to scrambling, branched below, becoming tufted, pubescent. Leaves opposite, sessile, crenate or serrate, decreasing in size above. Flowers solitary, axillary, shortly pedicellate, ebracteolate. Calyx 4-lobed; lobes straight. Corolla subrotate, 5-lobed; limb weakly bilabiate but not separated into galea and lip. Stamens 4, didynamous; anther thecae 2, equal, parallel, mucronate. Style simple, filiform; stigma entire. Capsule ovoid. Seeds many, white, longitudinally winged.
Monotypic genus: Hedbergia abyssinica (Hochst. ex Benth.) Molau, trop. Africa; sthn trop. Afr.: Zambia, Malawi. Molau described this genus as distinct from Bartsia L. by reason of its 5-lobed, subrotate not markedly bilabiate and galeate corolla.