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

by Franz Thonner

ORDER CENTROSPERMAE

SUBORDER CHENOPODIINEAE

[FAMILY 67.] CHENOPODIACEAE

Stem erect, ascending, or prostrate. Leaves exstipulate, sometimes wanting. Flowers inconspicuous, greenish. Perianth simple, of 1-5 imbricate segments, herbaceous or membranous, persistent, rarely wanting. Stamens as many as and opposite the perianth-segments or fewer, inserted on the receptacle or the base of the perianth. Anthers attached by the back, opening inwards or laterally by longitudinal slits, curved inwards in the bud. Ovary superior, rarely (Beta) half-inferior, 1-celled. Ovule 1, on a basal funicle, curved. Stigmas 2-5. Fruit dehiscing by a lid or indehiscent. Seed with a curved, peripheral embryo.—Genera 26, species 120. (SALSOLACEAE.) (Plate 40.)

1. Embryo spiral. Albumen wanting or separated in two parts by the embryo. 2
Embryo more or less ring- or horseshoe-shaped or folded together. Albumen wholly or partly enclosed by the embryo, rarely wanting. 11
2. Bracteoles small, scale-like. Perianth herbaceous or fleshy. Stigmas thread-shaped, papillose all round. Leaves glabrous, fleshy.—Species
10. Some are used as vegetables or for making soda. (Including
Chenopodina Moq., Lerchia Hall., Schanginia C. A. Mey., Schoberia C. A.
Mey., and Sevada Moq.) [Tribe SUAEDEAE.] Suaeda Forsk.
Bracteoles equalling or exceeding the perianth. Perianth usually membranous.
Stigmas papillose on the inside. Leaves usually hairy.
[Tribe SALSOLEAE.] 3
3. Seed horizontal. Disc usually inconspicuous. [Subtribe SODINAE.] 4
Seed vertical. Disc usually lobed. [Subtribe ANABASINAE.] 6
4. Perianth 5-lobed, hardening to the top and wingless in the fruit. Filaments flattened. Disc inconspicuous. Embryo in a conical spiral. Shrubs with continuous branches and alternate leaves.—Species 2. North
Africa to the Sahara. (Plate 40.) Traganum Del.
Perianth 4-5-parted or of 4-5 free segments, not hardening or at the base only and furnished with a horizontal wing in the fruit. 5
5. Branches jointed. Leaves scale-like, opposite, connate in pairs. Shrubs.
Perianth-segments free. Anthers blunt. Disc lobed, enlarged in the fruit. Embryo in a flat spiral.—Species 2. North Africa. Haloxylon Bunge
Branches continuous. Disc usually inconspicuous.—Species 20. Some of them are used as vegetables or in medicine or furnish soda. “Saltwort.”
(Including Caroxylon Thunb.) Salsola L.
6. Perianth of 2 inner and 3 outer segments of which two are in front and one behind. Fruiting perianth winged, not hardened. Seed compressed dorsally. Flowers solitary, more rarely in clusters, and then branches jointed and leaves opposite. 7
Perianth of 3 inner and 2 outer segments of which one is in front and one behind. Fruiting perianth more or less hardened. Seed compressed laterally. Branches continuous. 8
7. Branches jointed. Leaves opposite, sometimes reduced to scales. Filaments awl-shaped. Style short.—Species 5. North Africa and
Nubia. Some yield soda or are used medicinally. Anabasis L.
Branches continuous. Leaves alternate. Spinous shrubs. Flowers solitary.
Filaments flattened; connective pointed. Style long. Pericarp membranous.—Species 1. North Africa. Noaea Moq.
8. Perianth-segments united at the base, wingless in the fruit, but one of them sometimes produced into a prickle. Style long. Shrubs. 9
Perianth-segments free, winged in the fruit, at least some of them. Style short. Disc lobed. Leaves alternate. Flowers in clusters. 10
9. Leaves opposite. Flowers in pairs, hermaphrodite. Disc indistinct.—Species
1. Sahara. Nucularia Battand.
Leaves alternate. Flowers in clusters, polygamous. Disc lobed.—Species
2. North Africa and Northern Central Africa. Cornulaca Del.
10. Inner perianth-segments not winged in the fruit. Stamens with a 2-lobed connective. Shrubs.—Species 1. North Africa. (Under Halogeton
C. A. Mey.) Agathophora Fenzl
Inner and outer perianth-segments winged in the fruit. Stamens with
a blunt connective. Herbs.—Species 1. North-West Africa (Algeria).
Used as a vegetable or for making soda. Halogeton C. A. Mey.
11. (1.) Branches more or less distinctly jointed. Leaves little developed, glabrous. Flowers in clusters, usually of 3, arising in the axils of scale-like bracts or apparently sunk in hollows of the rachis and collected in cone-shaped inflorescences. Stamens 1-2. [Tribe
SALICORNIEAE.] 12
Branches continuous. Leaves well developed, usually hairy. Flowers solitary or in clusters, more rarely in spike-like inflorescences. Stamens
3-5, more rarely 1-2. 16
12. Bracts and upper leaves alternate. 13
Bracts and upper leaves opposite. 14
13. Perianth slightly flattened from the side, 4-5-toothed, surrounded by a wing-like border. Stamens 2. Ovule with a short funicle. Micropyle of the ovule and radicle of the embryo inferior. Low shrubs.—Species
1. North-West Africa (Algeria). Kalidium Moq.
Perianth flattened from the back, 3-toothed, without a wing-like border.
Ovule with a long funicle. Micropyle and radicle superior or ascending.—Species
2. North Africa to Nubia. Yield soda. Halopeplis Bunge
14. Bracts free, peltate, deciduous. Perianth 3-parted. Stamen 1, inserted in front. Ovule on a long, curved, almost ring-shaped funicle. Micropyle and radicle superior. Shrubs.—Species 1. North Africa to Eritrea. Yields soda. Halocnemum Marsch. Bieb.
Bracts united, persistent; flower-clusters apparently sunk in hollows of the branch-joints. Perianth 3-4-toothed or -cleft. Stamen 1, inserted behind, or stamens 2. Ovule on a short funicle. Micropyle and radicle inferior. 15
15. Seed smooth or tubercled; embryo curved; albumen abundant, lateral.
Stamens 2. Stigmas 2. Shrubs.—Species 3. North and Central
Africa. They yield soda and are used in medicine. Arthrocnemum Moq.
Seed hairy; embryo folded together; albumen scanty and central or wanting.—Species 4. Sea-coasts. They yield soda and are used in medicine. Salicornia L.
16. Flowers unisexual, sometimes intermixed with a few hermaphrodite, of two kinds, the male and hermaphrodite with a 3-5-parted perianth and without bracteoles, the female without a perianth, but with 2 sometimes united or 2-parted bracteoles. Stamens 3-5. Leaves glabrous, mealy or cottony, usually hastate. [Tribe ATRIPLICEAE.] 17
Flowers hermaphrodite, sometimes intermixed with similar unisexual ones, all with 4-5 perianth-segments. 19
17. Bracteoles small, narrow, free, unchanged in the fruiting stage, not enclosing the fruit. Flowers monoecious. Stamens 5. Shrubs.—Species
2. South Africa and St. Helena. Exomis Fenzl
Bracteoles large, broad, usually united and hardening, completely enclosing the fruit. 18
18. Bracteoles united nearly to the top, hardened in the fruit and sometimes prolonged into 2-4 prickles. Flowers dioecious. Stigmas 4-5. Stem and leaves glabrous. Herbs.—Species 1 (S. oleracea L., spinach).
Cultivated in the extra-tropical regions. It serves as a vegetable; the seeds are sometimes used for making bread. Spinacia L.
Bracteoles free and herbaceous, or more or less united, but not nearly to the top, and at length hardened. Stigmas 2-3. Stem and leaves clothed, when young, with bladdery hairs, afterwards mostly with a close minute whitish pubescence.—Species 20. Some are used as vegetables, for making soda, in medicine, or as ornamental plants. “Orache.” (Including
Obione Gaertn.) Atripex L.
19. Ovary half-inferior. Perianth-segments connivent in the fruit. Fruit dehiscing by a lid. Herbs with a fleshy taproot. Bracteoles usually present.—Species 3. North Africa and Cape Verde Islands; one of them (B. vulgaris L., beet) also cultivated in South Africa and Madagascar.
The latter species yields sugar, vegetables, fodder, and a substitute for coffee and tobacco. [Tribe BETEAE.] Beta L.
Ovary superior. Fruit indehiscent, rarely dehiscing by a lid, but then
perianth-segments spreading in the fruit. 20
20. Flowers with bracteoles, solitary. Perianth membranous, unchanged in the fruit; segments erect. Stigmas 2. Ovule on a long funicle.
Pericarp membranous. Herbs or undershrubs. Leaves subulate, rigid, pungent.—Species 1. North-West Africa (Algeria). [Tribe
POLYCNEMEAE.] Polycnemum L.
Flowers without bracteoles. 21
21. Perianth 4-5-lobed, membranous. Leaves narrow, clothed with thin hairs. [Tribe CAMPHOROSMEAE.] 22
Perianth 5-parted, rarely 4-parted or 5-lobed, more or less herbaceous.
Leaves usually broad and clothed with bladdery hairs. 25
22. Perianth unequally 4-toothed, scarcely changed in the fruit. Stamens
4. Seed erect. Embryo horseshoe-shaped. Flowers in spikes. Undershrubs.—Species
1. North Africa. Used medicinally. Camphorosma L.
Perianth 5-toothed, 5-lobed, or 5-cleft. Stamens 5. Seed nearly always horizontal. Embryo ring-shaped. Flowers solitary or in clusters, in the axils of the leaves. 23
23. Fruiting perianth unchanged and unappendaged. Undershrubs.—Species
3. North and South Africa. Chenolea Thunb.
Fruiting perianth winged, gibbous, or prickly. 24
24. Fruiting perianth gibbous or prickly.—Species 2. North Africa. (Echinopsilon
Moq., under Chenolea Thunb. or Kochia Roth). Bassia All.
Fruiting perianth with one or several wings.—Species 3. South Africa to
Hereroland and North Africa to Nubia. Kochia Roth
25. Fruit not enclosed in the perianth, dehiscing with a lid. Perianth-segments spreading, linear-oblong. Stamens 5, much shorter than the perianth.
Stigmas 2, short. Leaves elliptical or lanceolate, entire, glabrous.
Undershrubs.—Species 1. North-West Africa (Algeria). Oreobliton Durieu & Moq.
Fruit wholly or partly enclosed in the perianth, indehiscent. Leaves usually broad, toothed, and mealy or glandular-hairy.—Species 25.
Some of them yield edible seeds, dyes, and medicaments, or are used as vegetables or ornamental plants; several are poisonous. “Goosefoot.”
(Including Blitum L. and Roubieva Moq.) [Tribe CHENOPODIEAE.] Chenopodium L.

[FAMILY 68.] AMARANTACEAE

Leaves without stipules. Perianth more or less dry, simple, of 1-5 imbricate segments. Stamens as many as and opposite the perianth-segments or fewer. Anthers attached by the back, opening inwards by two longitudinal slits. Ovary superior, 1-celled. Ovules erect or suspended from a basal funicle, curved. Fruit dehiscing by a lid or indehiscent. Embryo surrounding the mealy albumen.—Genera 32, species 200. (Plate 41.)

1. Anthers 1-celled. Ovule 1. Herbs or undershrubs. Leaves opposite.
Inflorescences head-or shortly spike-shaped. [Subfamily GOMPHRENCIDEAE, tribe GOMPHRENEAE.] 2
Anthers 2-celled. [Subfamily AMARANTOIDEAE.] 4
2. Stigma 1, capitate. Fertile stamens alternating with staminodes.—Species
7. Some are used as ornamental plants, others are noxious weeds. (Including Telanthera R. Br.) [Subtribe FROEHLICHINAE.] Alternanthera Forsk.
Stigmas 2-4, subulate. [Subtribe GOMPHRENINAE.] 3
3. Filaments entire.—Species 1. Central Africa. (Philoxerus R. Br.) Iresine L.
Filaments fringed, toothed, or 3-parted.—Species 1. Tropical and South
East Africa. A weed, sometimes used as an ornamental plant. Gomphrena L.
4. Ovule 1. [Tribe AMARANTEAE.] 5
Ovules 2 or more, very rarely ovule 1, erect; in this case filaments united below into a membranous tube and flowers hermaphrodite. [Tribe
CELOSIEAE.] 32
5. Ovule erect. Radicle of the embryo descending. Filaments free or united in a ring at the base. Flowers unisexual, polygamous, or hermaphrodite but intermixed with sterile ones. Leaves alternate. [Subtribe AMARANTINAE.] 6
Ovule pendulous. Radicle of the embryo ascending. [Subtribe ACHYRANTHINAE.] 9
6. Perianth spreading. Filaments united at the base. Stigmas 3. Fruit a berry. Shrubs. Flowers polygamous, in spikes or racemes.—Species
1. Canary Islands. Bosia L.
Perianth erect. Herbs or undershrubs. 7
7. Flowers unisexual or polygamous; no sterile ones. Filaments free.—Species
20. Some of them have edible seeds or are used as vegetables, in medicine or as ornamental plants. (Including Albersia Kunth, Amblogyna
Rafin., and Euxolus Rafin.) Amarantus L.
Flowers hermaphrodite. Partial inflorescences consisting of one fertile and two sterile flowers. 8
8. Sterile flowers comb-shaped. Filaments free. Style short; stigma 2-lobed.—Species
1. Tropical and North Africa. Used as a vegetable. Digera Forsk.
Sterile flowers wing-shaped. Filaments united at the base. Style long; stigmas 2.—Species 1. Northern East Africa (Somaliland). Pleuropterantha Franch.
9. Flowers solitary in the axil of each bract. 10
Flowers in clusters of two or more; usually some of them sterile. 20
10. Spurious staminodes (sterile processes) interposed between the fertile stamens. 11
Spurious staminodes wanting. 18
11. Perianth densely covered with silky or woolly hairs. 12
Perianth glabrous or scantily hairy. 15
12. Perianth-segments firmly leathery, silky-hairy, 3-nerved. Shrubs. Leaves alternate, fleshy.—Species 1. South Africa to Damaraland. (Under
Sericocoma Fenzl). Calicorema Hook. fil.
Perianth-segments more or less membranous. 13
13. Branches jointed. Leaves very small, opposite, ovate, acuminate. Undershrubs.—Species
1. Southern West Africa (Hereroland). Arthraerua Schinz
Branches continuous. 14
14. Perianth-segments silky, more or less thickened and hardened at the base, 1-nerved. Flowers small. Ovary hairy. Stigma capitate.—Species
8. Southern and Central Africa. Sericocoma Fenzl
Perianth-segments woolly, not thickened. Flowers very small, in dense spikes.—Species 10. Some are used as vegetables or as ornamental plants. (Ouret Adans.) Aerva Forsk.
15. Spurious staminodes minute, narrow, acute, unappendaged. Perianth-segments brownish-red, stiff-leathery, large, oblong, 3-nerved. Inflorescence head-like, ovoid. Leaves usually alternate. Undershrubs.—Species
1. Southern West Africa (Angola and Congo). Mechowia Schinz
Spurious staminodes more or less quadrate, fringed or appendaged. Leaves opposite. 16
16. Spurious staminodes fringed below the top. Perianth-segments erect, oblong, blunt, thickened below. Flowers erect, spicate. Leaves small, sessile, linear-oblong. Herbs.—Species 1. Southern East Africa.
(Under Pandiaka Hook. fil.) Argyrostachys Lopr.
Spurious staminodes fringed at the top or prolonged into appendages.
Perianth-segments pointed. Flowers usually bent downwards. 17
17. Perianth-segments red or yellow, elliptical, hardened at the base, faintly
1-5-nerved. Shrubs or undershrubs.—Species 7. Central Africa to
Transvaal. Centema Hook. fil.
Perianth-segments white, green or brown, lanceolate, stiff-leathery, usually 3-ribbed.—Species 30. Some of them yield a substitute for soap or are used in medicine. (Including Achyropsis Moq. and Pandiaka
Moq.) (Plate 41.) Achyranthes L.
18. (10.) Stamens 1-2. Perianth-segments 3-5, membranous, woolly, 1-nerved.
Herbs.—Species 1. Tropics. Nothosaerua Wight
Stamens 4-5. 19
19. Outer perianth-segments densely clothed with silky hairs, faintly 3-nerved.
Style slender. Shrubs.—Species 2. Northern East Africa (Somaliland). Chionothrix Hook. fil.
Outer perianth-segments glabrous or scantily hairy, with 3 strong ribs.
Flowers greenish.—Species 15. Central and South East Africa. (Including
Psilostachys Hochst.) Psilotrichum Blume

AMARANTACEAE.