I7S 66 POLYGONACEAE 



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 

 «overs moncerious. [Subfamily RUMICOIDEAE, Tribe RUMICEAE.] 2 

 Stamens more than perianth-segments, rarely e(|ual in number, but then 5. 

 Herbs or undershrubs with hermaphrodite or polygamou-. flower?, 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 Xeck. 

 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 dj-eing, or in medicine. " Dock." Rumex L. 



3. Seed with ruminate albumen. Shrubs with 5, 7—10, or 20 —50 stamens. 



[Subfamily COCCCLOBOIDEAE.] 4 



Seed with homogeneous albumen. Herbs or undershrubs, more rarely 



shrubs with 6 or 12— t8 stamens. [Subfamily PCLYGONOIDEAE.] 5 



4 Flowers unisexual. Perianth-segmerjts 4 or 6, the outer deciduous. Stamens 



20 — 50. Erect shrubs or frees. — Species t. West Africa. [Tribe 



TRIPLARIDEAE.] Symmeria Benth. 



F'lowers 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 COCCOLO- 

 BEAE.] Brunnichia Banks 



5. Stem woody, shrubby. Leaves small. Stamens 6 or 12 — 18. Filaments 



united at the base. [Tribe ATRAPHAXH^EAE.] 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 POLYGONE AE.] 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. Embrj^o 

 lateral. Leaves ovate or orbicular. — Species i. 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 i. 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. 



]*erianth-segments not united below into a narrow tube 8 



8. Seed with broad, folded cotyledons. Perianth shorter than the fruit. 



Lea^'es cordate. — Species i [F. escnlentum Moench, buckwheat). 

 Cultivated as a cereal or fodder-plant. (Under Poly^omwi L.) 



Fagopyrum Gaertn. 



