Aristolochiaceae, Polygonaceae 39 



lobes or one lip. Stamens usually 6 or 12, free or united 

 to the style. Carpels (4-6) with numerous axile ana- 

 tropous ovules with two integuments. Fruit a capsule. 

 Seed with small embryo in copious endosperm. 



Tribe i. Asareae. Herbs with reniform leaves. 

 Flowers actinomorphic. 



Only genus (perianth campanulate) : Asarum. 



Tribe 2. Aristolochieae. Flowers zygomorphic. 



Only British genus (perianth tubular, dilated at 

 base) : *Aristolochia. 



Order 8. Polygonales. Leaves alternate, usually 

 with sheathing bases. Flowers haplochlamydeous to 

 heterochlamydeous, actinomorphic. Ovary superior, 

 i-locular, with one basal orthotropous ovule with two 

 integuments. 



Fam. Polygonaceae. Herbs, rarely shrubs or trees. 

 Leaves usually entire with scarious or fleshy amplexicaul, 

 stipular sheath. Flowers small in compound inflores- 

 cences, cyclic or partially spiral, usually hermaphrodite. 

 Tepals 3-6 free. Stamens 5-9. G(3) or (2) with as 

 many styles. Fruit a nut. Seed with copious mealy 

 endosperm. Embryo straight or curved. 



Subfamily i. Rumicoideae, Flowers cyclic. Endo- 

 sperm not fissured. 



Tribe Rumiceae, Leaves with conspicuous sheath. 

 Stamens in one whorl. Fruit not winged. Rumex. 

 Stamens in two whorls. Fruit winged. 



Rheum (including Oxyria), 



Subfamily 2. Polygonoideae. Flozvers mostly spiral 

 Endosperm not fissured. 



