The flowering plants of Africa / An analytical key to the genera of African phanerograms - Franz Thonner

SUBORDER ICACININEAE

Trees or shrubs. Leaves entire toothed or lobed, without stipules. Flowers regular, 4-5-merous. Stamens as many as the petals or perianth-segments and alternate with them. Anthers opening by 2 longitudinal slits. Ovary superior, 1-celled. Ovules 2, pendulous, inverted, with dorsal raphe. Style 1 or 0. Fruit a drupe. Seed 1, with a thin testa, without an aril.—Genera 19, species 90. Tropical and South Africa. (Under OLACINEAE.) (Plate 84.)

1. Pericarp warty or spiny on the inner face. Embryo equalling the albumen.
Climbing or twining shrubs. Leafstalk terete. [Tribe PHYTOCRENEAE.] 2
Pericarp smooth or wrinkled on the inside. Leaves entire. 7
2. Perianth simple, 3-5-parted. Stigma sessile. Leaves palminerved. 3
Perianth, at least in the female flowers, consisting of a sometimes very small calyx and a corolla of united petals. Leaves penninerved. 5
3. Flowers solitary or in pairs in the axils of the leaves, hermaphrodite. Stem tuberous, with slightly twining branches. Leaves undivided, wavy at the margin.—Species 1. East Africa (Somaliland). Trematosperma Urban
Flowers in heads or spikes, dioecious. 4
4. Flowers in heads arranged in spikes or panicles. Perianth of the male flowers 3-lobed.—Species 3. West Africa. Polycephalium Engl.
Flowers in spikes. Perianth usually 4-parted.—Species 15. Tropical and South Africa. Pyrenacantha Hook.
5. Calyx minute. Corolla not enlarged in the fruit. Flowers in spikes arising from the lower part of the stem. Leaves oval.—Species 1.
Madagascar. Endacanthus Baill.
Calyx distinctly developed, at least in the female flowers. Corolla enlarged in the fruit. 6
6. Calyx of the male flowers 5-toothed. Petals 5. Filaments rather long.
Anthers linear. Flowers in spikes at the nodes of the older branches.
Leaves lanceolate.—Species 1. West Africa (Cameroons). Stachyanthus Engl.
Calyx of the male flowers indistinct or wanting. Petals 4. Filaments short. Anthers ovate. Flowers in spikes or heads. Species 7.
West Africa. Chlamydocarya Baill.
7. (1.) Flowers dioecious, with a corolla of united petals, with or without a calyx. Stamens with flat filaments; anthers opening inwards. Embryo nearly equalling the albumen. Climbing shrubs, usually with tendrils.
Leaves opposite. Flowers in panicles.—Species 6. Tropics. [Tribe
IODEAE.] Iodes Blume
Flowers hermaphrodite or polygamous, rarely unisexual, but then with a calyx and a corolla of free petals, or without a corolla, and the anthers
opening outwards. Embryo usually much shorter than the albumen.
Trees or erect, rarely climbing shrubs; in the latter case leaves alternate or flowers in spikes. [Tribe ICACINEAE.] 8
8. Flowers unisexual, dioecious. Calyx 5-partite. Petals minute and free, or wanting. Anthers turned outwards. Ovary with a ring-shaped appendage at the top. Trees. Leaves alternate. Flowers in panicles.—Species
2. Madagascar and neighbouring islands. Grisollea Baill.
Flowers hermaphrodite or polygamous. Perianth consisting of a calyx and a corolla. 9
9. Petals free. Sepals usually united high up. 10
Petals more or less united. Sepals usually united at the base only. 14
10. Embryo nearly as long as the albumen. 11
Embryo much shorter than the albumen. 12
11. Petals bearded within. Disc present. Style long; stigma small or shield-shaped.
Fruit with a crusty endocarp. Embryo with flat cotyledons.
Shrubs with ascending or somewhat twining branches.—Species 7.
Tropics. Some have edible fruits or seeds. Icacina Juss.
Petals not bearded within. Disc absent. Fruit with a woody endocarp and a fleshy mesocarp. Embryo with folded cotyledons. Climbing shrubs.—Species 2. Equatorial West Africa. The fruits and seeds are eaten and used medicinally. Lavigeria Pierre
12. Stem climbing. Flowers in spikes. Petals hairy outside. Disc present.
Ovary without swellings. Style terminal; stigma slightly lobed.—Species
6. Tropics. Desmostachys Planch. & Miers
Stem erect, tree-like. Flowers in fascicles or panicles. Ovary with 2 swellings. Style lateral. 13
13. Flowers in axillary fascicles. Filaments broadened below. Ovary usually with two narrow swellings at the top.—Species 12. Central Africa.
(Under Apodytes Mey.) Rhaphiostyles Planch.
Flowers in terminal panicles. Filaments awl-shaped. Ovary with two broad swellings on the ventral face.—Species 10. Tropical and South
Africa. Several species yield timber or edible fruits. (Plate 84.) Apodytes E. Mey.
14. Petals united at the base or nearly to the middle. 15
Petals united beyond the middle. 16
15. Petals imbricate in the bud. Style short. Leaves opposite. Flowers in repeatedly forked cymes.—Species 4. South Africa and Madagascar. Cassinopsis Sond.
Petals valvate in the bud. Style long. Leaves alternate. Flowers in few-flowered fascicles or panicles.—Species 9. Central Africa. (Including
Alsodeiidium Engl.) Alsodeiopsis Oliv.
16. Petals imbricate in the bud. Sepals and stamens unequal. Disc indistinct.
Stigma sessile. Leaves opposite, elliptical. Flowers in panicles.—Species 1. Madagascar. Tridianisia Baill.
Petals valvate in the bud. 17
17. Petals bent backwards at the tip. Disc thick. Style short. Leaves opposite, lanceolate. Flowers in few-flowered axillary cymes.—Species
1. West Africa (Congo). Acrocoelium Baill.
Petals bent inwards at the tip. Disc absent. Leaves alternate. 18
18. Sepals united at the base only. Filaments adnate to the corolla-tube throughout their whole length, without appendages. Style long, filiform. Ovary and fruit without a swelling.—Species 5. Tropics. Leptaulus Benth.
Sepals united high up. Filaments free from the corolla, with two tufts of hairs at the apex. Style short, conical. Ovary and fruit with a lateral swelling. Flowers in head-like cymes.—Species 1. West
Africa. Lasianthera Beauv.

SUBORDER SAPINDINEAE

[FAMILY 133.] ACERACEAE

Trees or shrubs. Leaves opposite, palmately lobed, without stipules. Flowers in terminal corymbs, regular, polygamous. Sepals 5, free. Petals 5, free. Stamens 8, very rarely 4 or 12, perigynous, inserted on the inner edge of the thick disc. Filaments free. Ovary superior, 2-lobed and 2-celled, with 2 ovules in each cell. Styles 2 or a single style with 2 branches or stigmas. Fruit winged, splitting into 2 mericarps. Seeds exalbuminous. (Under SAPINDACEAE.)

Genus 1, species 4. North-west Africa. They yield timber, tanning bark, and sugar, and serve as ornamental plants. “Maple.” Acer L.

[FAMILY 134.] SAPINDACEAE

Trees or shrubs, rarely (Cardiospermum) herbs or undershrubs. Leaves alternate, usually compound. Flowers in racemes or panicles, rarely solitary or in clusters, polygamous, rarely unisexual. Petals 4-5, mostly with a scale on the inner face, or absent. Stamens 4-24, usually 8, inserted within the disc, rarely upon it; sometimes disc indistinct. Anthers opening inwards by 2 longitudinal slits. Ovary superior, 2-8-, usually 3-celled, sometimes not quite completely septate or with a single fertile cell, frequently lobed. Ovules 1-2, rarely (Cossignia) 3 in each ovary-cell, curved. Style 1, undivided, rarely cleft. Seeds exalbuminous; embryo usually curved.—Genera 51, species 200. (Including DIDIEREACEAE.) (Plate 85.)