Annual herbs. Leaves paired, shortly petiolate; stipules small, with several deltoid segments from a short base. Flowers bisexual, small, dimorphic, some flowers with anthers included and style exserted and others completely vice versa, in small sessile terminal heads. Calyx: tube short; lobes small, 3 or 4, sometimes 1 enlarged and rest minute, or all minute. Corolla: tube narrowly funnel-shaped; lobes 3 or 4, oblong; throat hairy. Ovary 2-locular; ovules solitary in each locule, pendulous; style filiform; stigma bifid, lobes filiform. Fruit ovoid, indehiscent, but longitudinally grooved and where fruit breaks off a little cup is left being the persistent woody flanged pedicel; between this flange and base of fruit masses of raphides present. Seeds narrowly ellipsoid or ovate in outline, strongly compressed.
Monotypic genus: Paraknoxia parviflora (Stapf ex Verdc.) Verdc. ex Bremek., E and C Africa; sthn trop. Afr.: Angola, Zimbabwe, Malawi; close to Pentanisia.
Tall trees, sometimes with small, knee-like pneumatophores; bark grey to brown, irregularly cracked and flaking; branchlets often 4-angled, glabrous or hairy. Leaves large, petiolate, oblong to elliptic, to broadly ovate, entire, with small domatia, glabrous above, mostly hairy beneath. Inflorescences terminal and/or axillary, of 3-many dense spherical heads with pubescent receptacles, flowering branches developing monopodially; bracteoles linear-spathulate, surrounding the free, sessile flowers; buds pubescent at apex. Calyx tubular, limb truncate or distinctly lobed; epicalyx sometimes present. Corolla: tube funnel-shaped, glabrous; lobes erect, pubescent outside, terminated by short, subulate, glabrous, deciduous appendages. Anthers included. Ovaries free, 2-locular; ovules many, ascending and imbricate on subpeltate placentas; style distinctly exserted, pollen presenter ovoid or mitriform. Fruit dry, dehiscing septicidally, endocarp splitting into two valves, each with rounded lobes. Seeds small, with winged margin.
Species 3, trop. Africa; sthn trop. Afr. 2 or 3, Angola, Zambia, Malawi.
Mitragyna Korth., in part; Halle: 32 (1970); Ridsdale: 43 (1978); White et al.: 479 (2001).
Perennial forest floor herbs, mostly with slender creeping stems rooting at nodes. Leaves opposite, with mostly long petioles; blades ovate-cordate to rounded-reniform; stipules interpetiolar, ovate, entire or bilobed at apex. Flowers bisexual, sometimes heterostylous, mostly in terminal umbels or sometimes solitary, often on long peduncles held erect from main stems, occasionally with an involucre of quite conspicuous bracts. Calyx: tube obovoid, limb short, 5-7-lobed; lobes subulate or linear, spreading or reflexed, persistent. Corolla cylindric or funnel-shaped; lobes 4-7, spreading or recurved; throat pilose inside. Stamens 4-7, arising in corolla tube; filaments filiform; anthers dorsifixed, included or exserted. Disc swollen. Ovary 2-locular; ovules solitary in each locule, erect from base, anatropous; style slender, included or exserted; stigma lobes 2, linear, densely papillate or stigma subcapitate-bifid. Fruit a drupe, fleshy, containing 2 pyrenes; pyrenes plano-convex, dorsally compressed, obtusely ribbed, rugulose and often with an annular area at junction of ventral and dorsal surfaces, 1-seeded. Seeds same shape as pyrenes, ventral surface plane; testa membranous; endosperm corneous.
Species +/- 15, tropics of Old and New World; sthn trop. Afr. 3, Angola, Zambia, Zimbabwe, Malawi, Mozambique.
Small erect shrubs, invariably turning blackish on drying and with distinctly discolorous leaves. Leaves very shortly petiolate, elliptic to lanceolate, rather thick, closely placed, lateral nerves invisible or very obscure; stipule-sheath usually hairy, divided into several subulate fimbriae. Flowers heterostylous, small in many-flowered, dense, terminal corymbs or panicles. Calyx: lobes 4, triangular or lanceolate, often with fimbriae between. Corolla shortly subcylindric, slightly widened above; lobes 4; throat glabrous or sparsely hairy inside. Stamens well exserted in short-styled flowers. Ovary 2-locular; ovules few on peltate placentas; style filiform; stigma lobes subglobose. Capsule depressed hemispherical, produced into a conical beak which splits loculicidally and septicidally into 4 diverging valves. Seeds few, much compressed, elliptic or oblong, sometimes subangular and often slightly winged at both ends or all round, reticulate.
Species 2, very closely allied, upland trop. Africa; sthn trop. Afr. 2, Angola, Zambia, Malawi.
Geofrutices with massive woody underground parts and tender, hardly branched supraterranean twigs; +/- all parts densely covered with long soft hairs. Leaves suborbicular, coriaceous to almost succulent, apex +/- emarginate, base widely cuneate; venation subpalmate; petiole slender; stipules interpetiolar, ovate with acute tip, free to base and not sheathing. Inflorescence: flowers solitary, pseudo-axillary; bracteoles ovate with acute tip. Flowers with left-contorted aestivation. Calyx long-tubular; lobes 5, narrowly triangular. Corolla: tube slender; lobes 5, narrow, +/- 1/2 as long as tube. Stamens: anthers 5, sessile in uppermost part of corolla tube, with small, narrowly triangular, sterile apical appendage; pollen in tetrads. Ovary 2-locular, with 2 peltate axile placentas with many ovules adnate to +/- entire septum; style slightly surpassing anthers, almost thread-like but upper part slightly swollen, terminating in 2 short, papillar stigmatic lobes. Fruit unknown.
Monotypic genus: Ganguelia gossweileri (S.Moore) Robbr., endemic to south-central Angola.
Oxyanthus DC. in part as to O. gossweileri S.Moore.
Shrubs or small trees; branches glabrous or pubescent. Leaves opposite, petiolate; domatia present or absent; stipules triangular. Flowers bisexual, sweetly scented, 5-merous, pedicellate in pedunculate axillary cymes; bracts and bracteoles present. Calyx glabrous or pubescent; tube extremely short; lobes ovate. Stamens arising at top of corolla tube, exserted and spreading when mature; filaments short; anthers dorsifixed near base, narrowly oblong, with distinctly apiculate connective. Disc annular. Ovary 2-locular; placentas small, attached near top of locules, bearing 2 pendulous ovules or rarely one ovule on a larger placenta; style short, subulate, pubescent; stigmatic club deeply bifid, but two halves often held together; 5 membranous ciliate wings present on each lobe. Fruit fleshy, globose, 2-locular; calyx limb persistent. Seeds (2-)4 per fruit, +/- 1/4(-1/2)-spherical, finely reticulate; endosperm ruminate; placenta forming a small aril-like structure at apex of pair of seeds.
Subshrubby herbs (suffrutices) or shrubs, completely softly tomentose, mostly much branched. Leaves opposite, or less often in whorls of 3, shortly petioled; stipules with triangular or sheathing connate bases and subulate appendages. Flowers relatively large, in subsessile or shortly pedunculate, dense, few- to many-flowered cymes. Calyx: tube globose with a short +/- subundulate limb or short, triangular teeth. Corolla thick, cylindric or obovoid, obtuse or shortly acuminate at apex in bud; mostly yellow or greenish, densely tomentose; tube cylindric, glabrous or hairy at throat, with a ring of deflexed hairs inside; lobes reflexed, obtuse or shortly apiculate. Stamens inserted at throat; anthers exserted or partly exserted. Ovary (3)4- or 5-locular, each locule with a pendulous ovule; style slender, exserted; pollen presenter cylindric or coroniform, sulcate, (3)4- or 5-lobed at apex. Fruit drying black, globose, crowned with calyx limb, sometimes ribbed, containing (3)4 or 5 pyrenes, +/- glabrous. Pyrenes thinly woody, not crested around apex, point of attachment +/- beaked, very slightly textured. Cotyledons very much shorter than radicle.
Deciduous small shrubs or trees; branches with very unequal internodes, some slender and elongated, others at apices very condensed; petiolar scars prominent Leaves opposite, petiolate, tufted at ends of shoots; blades thin, with pubescent domatia; stipules scarious, persistent. Flowers fragrant, solitary, terminal, 5(6-8)-merous, surrounded at base by scarious scales. Calyx: tube cylindric-turbinate; free tubular part of limb very short; lobes elongate, persistent. Corolla turning black on drying; tube short to very long, cylindric, apical part narrowly to broadly funnel-shaped, tube pubescent towards base; lobes contorted, overlapping to the left. Stamens sessile, apices of anthers just about reaching mouth of throat; pollen grains in tetrads, golden yellow. Ovary with 2 placentas forming 2 locules; ovules many; style swollen into an ellipsoid swelling at level of anthers with 2 closely adnate stigmatic lobes. Fruit globose or pyriform, crowned with persistent calyx lobes; peduncle accrescent. Seeds irregularly lenticular, compressed.
Species 2, trop. Africa; sthn trop. Afr. 2, Angola.
Erect or scrambling shrubs, entirely glabrous (except inside of corolla tube); some lateral branches modified into paired, straight supra-axillary spines held at right angles. Leaves opposite, petiolate, +/- elliptic, usually with small ciliate pit domatia; stipules subulate, slightly connate at base. Flowers bisexual, rather large, 5-merous, axillary or supra-axillary, solitary on both sides of node, sweetly scented at night; pedicels well-developed. Calyx: tube short, with colleters inside; lobes narrowly triangular. Corolla funnel-shaped with strong midpetaline nerves, pilose inside, glabrous outside; lobes ovate-triangular, much shorter than tube. Anthers included, sessile in uppermost portion of tube. Ovary 1-locular with 2 opposing parietal placentas which may be +/- joined to form a +/- 2-locular ovary; ovules deeply embedded in placentas. Fruit globose or ellipsoid, slightly ribbed, crowned with persistent calyx; testa thin, leathery. Seeds 10-15, lenticular, embedded in pulpy placental tissue.
Species 4, trop. Africa, 3 in W, 1 in E and SE; sthn trop. Afr. 2, Angola, Zimbabwe, Mozambique.
Stoloniferous creeping herbs rooting at nodes, with erect flowering branches, or sometimes erect shrubs. Leaves opposite, in 2-6 pairs on flowering stems; stipules bifid at apex or divided into 2 completely separate lobes; a membranous cylindric or cupular sheath present at nodes inside stipules. Inflorescences terminal or rarely axillary, +/- capitate, often with a cup-like involucre. Flowers sessile or subsessile, 5-merous, distinctly or obscurely heterostylous. Corolla: funnel-shaped. Stamens arising in middle of corolla tube; anthers linear or oblong. Ovary 2-locular with a single erect ovule per locule; style bifid. Fruit depressed-globose, usually orange, sometimes red, inflated, full of watery juice, crowned with persistent calyx; pyrenes 2, semi-ellipsoid, brittle, dorsal face convex and not ribbed, ventral face with 1 or 2 grooves, basally dehiscent by 2 short lateral fissures. Seeds semi-ellipsoid, with entire albumen.
Species 12, trop. Africa; sthn trop. Afr. 3, Angola.