ORDER POLYGONALES
[FAMILY 66.] POLYGONACEAE
Leaves alternate, undivided or pinnately cleft, provided at the base with a stem-clasping sheath. Flowers regular. Perianth-segments 3-6. Stamens 4-50. Ovary superior, 1-celled. Ovule 1. Styles 2-4, free or united at the base. Fruit a nut. Seed with an abundant, mealy albumen and a usually lateral embryo.—Genera 9, species 120. (Plate 39.)
1. Stamens as many as perianth-segments, 6, rarely 4; occasionally fewer than perianth-segments, and then stamens 4-5 and perianth-segments 5-6 in the male, 6 in the female flowers; in this case stem herbaceous and flowers monoecious. [Subfamily RUMICOIDEAE, Tribe RUMICEAE.] 2
Stamens more than perianth-segments, rarely equal in number, but then 5.
Herbs or undershrubs with hermaphrodite or polygamous flowers, or shrubs. 3
2. Perianth at the time of maturity firm, tubular, tightly clasping the fruit.
Flowers unisexual. Annual herbs.—Species 2. North and South
Africa, also naturalized in the Mascarene Islands. Emex Neck.
Perianth at the time of maturity more or less membranous, not tubular and not clasping the fruit very tightly.—Species 45. Some are used as vegetables, for tanning and dyeing, or in medicine. “Dock.” Rumex L.
3. Seed with ruminate albumen. Shrubs with 5, 7-10, or 20-50 stamens.
[Subfamily COCCOLOBOIDEAE.] 4
Seed with homogeneous albumen. Herbs or undershrubs, more rarely shrubs with 6 or 12-18 stamens. [Subfamily POLYGONOIDEAE.] 5
4. Flowers unisexual. Perianth-segments 4 or 6, the outer deciduous. Stamens
20-50. Erect shrubs or trees.—Species 1. West Africa. [Tribe
TRIPLARIDEAE.] Symmeria Benth.
Flowers hermaphrodite. Perianth-segments 5, united at the base into a tube becoming two-winged in fruit. Stamens 5-10. Mostly climbing, tendril-bearing plants.—Species 3. West Africa. [Tribe COCCOLOBEAE.] Brunnichia Banks
5. Stem woody, shrubby. Leaves small. Stamens 6 or 12-18. Filaments united at the base. [Tribe ATRAPHAXIDEAE.] 6
Stem herbaceous or woody at the base only. Stamens 8, more rarely
5-7. Filaments free, but sometimes inserted on a ring-shaped disc.
[Tribe POLYGONEAE.] 7
6. Perianth-segments 4, the inner much enlarged in fruit. Stamens 6, the outer with a callosity at the base. Stigmas 2. Fruit glabrous. Embryo lateral. Leaves ovate or orbicular.—Species 1. Egypt. Atraphaxis L.
Perianth-segments 5-6, not enlarged in fruit. Stamens 12-18, with
a hairy appendage at the base. Stigmas 4. Fruit bristly. Embryo axile. Leaves linear or subulate.—Species 1. North Africa. Calligonum L.
7. Perianth-segments of the hermaphrodite and female flowers united below into a narrow tube. Flowers polygamous.—Species 17. Central and
South Africa. Some are used as vegetables and for making bread.
(Including Raphanopsis Welw.) (Plate 39.) Oxygonum Burch.
Perianth-segments not united below into a narrow tube. 8
8. Seed with broad, folded cotyledons. Perianth shorter than the fruit.
Leaves cordate.—Species 1 (F. esculentum Moench, buckwheat).
Cultivated as a cereal or fodder-plant. (Under Polygonum L.) Fagopyrum Gaertn.
POLYGONACEAE.
FLOW. PL. AFR.
Pl. 39.
J. Fleischmann del.
Oxygonum sinuatum (Hochst. and Steud.) Benth. and Hook.