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

by Franz Thonner

A Flowering branch. B Flower cut lengthwise. C Cross-section of ovary.

31. Filaments awl-shaped. Petals 5, linear lanceolate or oblong. Flowers rather large.—Species 1. Cultivated and naturalized in the tropics.
Yields timber, fragrant flowers, and medicaments. Murraya L.
Filaments broadened below. Petals 4-5, elliptical or roundish. Flowers rather small.—Species 6. Central and South Africa. Some are used medicinally. (Including Myaris Presl). Clausena Burm.
32. Ovary with 4-8 ovules in each cell. Anthers oblong. Pericarp leathery.
Seed-coat white, leathery. Leaves leathery.—Species 4. Cultivated; also naturalized in the tropics. They serve as ornamental plants and afford wood, fragrant flowers, and edible fruits (especially oranges and citrons) from which drinks, medicaments, and perfumes are prepared. Citrus L.
Ovary with numerous ovules in each cell. Anthers linear. Pericarp hard. Leaves with 3 leaflets. 33
33. Stamens 10. Seed-coat smooth. Leaves leathery.—Species 1. Region of the great lakes. Balsamocitrus Stapf
Stamens numerous. Seed-coat woolly and sticky. Leaves herbaceous.—Species
1. West Africa. Yields timber and is used in medicine. Aegle Correa

[FAMILY 116.] SIMARUBACEAE

Shrubs or trees. Leaves simple or pinnate, not gland-dotted. Flowers in spikes racemes or panicles, regular. Sepals 2-5. Petals 3-9, free. Disc usually present. Anthers versatile, opening inwards by longitudinal slits. Carpels free or united and then forming a several-celled ovary. Ovules 1-2, pendulous or laterally attached. Seeds with a very thin albumen or without albumen.—Genera 16, species 40. Tropical and South Africa. (Under RUTACEAE.) (Plate 74.)

1. Carpels 5, free, 2-ovuled. Disc indistinct. Stamens 5-10, without an appendage. Corolla yellow. Fruit drupe-like. Embryo curved, with
a large radicle. Shrubs. Leaves undivided.—Species 1. Tropics.
[Subfamily SURIANOIDEAE.] Suriana L.
Carpels united at least by the base or the apex of the style, 1-ovuled.
Disc distinctly developed. Embryo with a very short radicle. [Subfamily
SIMARUBOIDEAE.] 2
2. Filaments with a scale-like appendage at the base. [Tribe SIMARUBEAE.] 3
Filaments without a scale at the base. 9
3. Stamens 6-14, twice as many as the petals. Anthers oblong or oval. 4
Stamens 15-18, thrice as many as the petals or more. Anthers linear.
Ovaries 5. Style 1. Corolla red. Trees. Leaves pinnate. [Subtribe
MANNIINAE.] 8
4. Ovaries and style-tips united. Fruit a drupe with 4-5 stones. Embryo curved. Shrubs. Leaves compound.—Species 2. Central Africa.
[Subtribe HARRISONIINAE.] Harrisonia (R.Br.) Juss.
Ovaries free. Styles united. Fruit consisting of 1-5 nuts or drupes.
[Subtribe SIMARUBINAE.] 5
5. Leaves undivided. Flowers in umbels. Calyx 3-5-lobed, imbricate in bud. Petals with contorted aestivation. Filaments with a minute scale at the base. Style long; stigma small, entire. Fruits woody.
Trees.—Species 2. Madagascar. Used medicinally. Samadera Gaertn.
Leaves pinnate. Flowers in racemes or panicles. 6
6. Calyx 5-parted, imbricate in bud. Petals 5, with contorted aestivation.
Filaments with a short scale. Style long; stigma slightly 5-lobed.
Leaflets lanceolate, acuminate.—Species 1. West Africa. Yields arrow-poison and is used in medicine. Quassia L.
Calyx 2-4-lobed or -cleft. Petals with imbricate aestivation. Filaments with a long scale. Style short. Flowers in panicles. 7
7. Calyx 4-, rarely 5-lobed. Petals 4, rarely 5. Fruits woody. Leaflets oblong or obovate.—Species 3. Equatorial regions. The seeds yield a fat. (Under Quassia L.) Odyendea (Pierre) Engl.
Calyx at first closed, later on unequally 2-4-cleft. Petals 5, rarely 6-9.
Stigma 5-parted. Fruits drupe-like.—Species 4. Central Africa.
They yield timber, oily seeds, and medicaments. Hannoa Planch.
8. Calyx shortly lobed. Anthers shorter than the filaments. Ovaries united below. Leaflets with a spoon-shaped appendage at the tip.—Species
1. West Africa (Cameroons). Pierreodendron Engl.
Calyx deeply divided. Anthers longer than the filaments. Ovaries free.
Leaflets with an awl-shaped appendage at the tip.—Species 1. West
Africa. Mannia Hook. fil.
9. (2.) Stamens 4-6. Carpels free, either as to the ovaries or as to the styles. Flowers usually polygamous. 10
Stamens 8-10. Fruit drupe-like. Trees. 12
10. Sepals 3. Petals 3. Stamens 6. Carpels 2, united at the base. Stigma subsessile, discoid. Fruit 2-celled, winged. Leaves undivided.—Species
1. Seychelles. [Tribe SOULAMEEAE.] Soulamea Lam.
Sepals, petals, stamens, and carpels 4. Stigma small. Leaves pinnate. 11
11. Ovaries and styles free or united at the base only. Petals short. Fruit consisting of 4 drupes. Rusty-hairy plants.—Species 5. Central
Africa. Used medicinally. [Tribe PICRASMEAE.] Brucea J. S. Muell.
Ovaries united; styles free. Petals long. Fruit separating into 4 leathery mericarps suspended from a central column.—Species 5. Central
Africa. [Tribe KIRKIEAE.] Kirkia Oliv.
12. Carpels free for the greater part. Leaves pinnate.—Species 1. Madagascar.
Poisonous. Perriera Courchet
Carpels wholly united. Leaves undivided. Flowers hermaphrodite. 13
13. Stigma 2-parted. Ovary 2-celled. Disc ring-shaped, lobed. Anthers oblong. Flowers solitary or in clusters in the axils of the leaves.—Species
1. South Africa. (Under Nectaropetalum Engl.) Peglera Bolus
Stigma entire. Disc cushion-shaped. Anthers ovate. Flowers in panicles.
[Tribe IRVINGIEAE.] 14
14. Ovary 4-5-celled. Fruit broader than long, angled, 4-5-celled, with
a thin fleshy layer.—Species 3. Equatorial West Africa. Klainedoxa Pierre
Ovary 2-celled. Fruit oblong, 1-2-celled. 15
15. Fruit much compressed, broadly winged all round, 2-celled, 2-seeded, with a thin fleshy layer.—Species 2. Equatorial West Africa. (Under
Irvingia Hook. fil.) Desbordesia Pierre
Fruit slightly compressed, not winged, 1-celled, 1-seeded, with a thick fleshy layer.—Species 5. Central Africa. They yield timber, edible fruits, and oily seeds (dika). (Including Irvingella van Tiegh.) (Plate
74.) Irvingia Hook. fil.

[FAMILY 117.] BURSERACEAE

Trees, rarely shrubs. Bark resinous. Leaves usually pinnate. Flowers panicled, regular, mostly polygamous. Perianth consisting of a calyx and a corolla of 3-5 free petals. Stamens twice as many as the petals, inserted on the margin or the outside of the disc, rarely within. Anthers versatile, opening inwards by longitudinal slits. Ovary 2-5-celled. Ovules 2 in each cell, pendulous or attached laterally. Style simple or wanting; stigma lobed. Fruit drupe-like, but sometimes dehiscent. Seeds exalbuminous. Embryo with a superior radicle and usually folded or twisted cotyledons.—Genera 7, species 160. Tropical and South Africa. (Under TEREBINTHACEAE). (Plate 75.)

1. Receptacle concave; tube-, cup-, or urn-shaped; sepals, petals, and stamens inserted at its upper rim. Sepals 4 and petals 4, valvate in bud. Ovary
2-3-celled. Fruit drupaceous, but dehiscent, with a 2-3-celled stone; one cell only fertile.—Species 110. Tropical and South Africa.
Several species yield timber and odorous resins (especially myrrh) which are used for preparing varnish, incense, and medicines. Some are also used as hedge plants. (Balsamea Gled., Balsamodendron Kunth. including Hemprichia Ehrenb. and Hitzeria Klotzsch). Commiphora Jacq.
Receptacle flat or convex, usually bearing a free disc, outside of which the sepals and petals are inserted. Leaves pinnate. Trees. 2
2. Flowers 3-merous. Petals valvate in bud. Fruit with a 2-3-celled stone, indehiscent, sometimes only one cell fertile. 3
Flowers 4-5-merous. Fruit with 2-5 stones. 5
3. Fruit depressed, obliquely hemispherical, broader than long, with a lateral style and 1-2 fertile cells; endocarp thin, mesocarp rather thick.
Embryo with a short radicle and thick, pinnately divided cotyledons.
Stamens inserted outside the thick disc. Ovary 3-celled; one cell
sterile.—Species 6. Equatorial West Africa. They yield timber, edible fruits, and medicaments. (Under Pachylobus Don or Santiria
Blume) Santiriopsis Engl.
Fruit oblong, ovate, or subglobose. 4
4. Fruit with 2 cells, one of which is sterile, and with a terminal style or style-scar; endocarp thin crusty, mesocarp thick fleshy. Embryo with
a long radicle and thick, much divided cotyledons. Ovary 2-celled.
Sepals united at the base.—Species 13. West Africa. They yield timber, resin, and edible oily fruits (safu). (Under Canarium L.)
(Plate 75.) Pachylobus Don
Fruit with 3 cells, two of them sometimes sterile; endocarp usually thick, woody or bony; mesocarp usually thin. Embryo with a short radicle and slightly divided cotyledons. Ovary 3-celled. Sepals united high up.—Species 13. Tropics. Some species yield timber, resin (elemi) used in medicine and manufacture, and edible oily fruits and seeds. Canarium L.
5. Disc situated outside the stamens. Petals 5, imbricate in bud. Ovary
5-celled. Fruit top-shaped, with 5 stones, dehiscent.—Species 1.
Equatorial West Africa. Yields timber and an aromatic resin. Aucoumea Pierre
Disc situated inside the stamens. 6
6. Petals 4-5, valvate in bud. Ovary 4-5-celled. Fruit globular or ovoid.
Species 4. Madagascar and Mascarenes. They yield timber and resin. (Marignia Comm.) Protium Burm.
Petals 5, imbricate in bud. Ovary 2-3-celled. Fruit with 2-3 stones, dehiscent. Flowers hermaphrodite.—Species 15. Central Africa.
The resin of several species (frankincense) is used as an incense and in medicine. Boswellia Roxb.

[FAMILY 118.] MELIACEAE