202 DICOTYLEDONS. ARISTOLOCHIJE. 



ORDER V. URTICE^E. 



Flowers perfect, or with the anthers and pistils distinct. Peri- 

 anth free, 3 5-cleft, persistent. Stam. 3 5, hypogynous, 

 usually with an elastic filament. Ovary 1. Style simple or 

 double or none. Stigma simple or double. Ackenia, or little 

 Drupes, covered with the persistent perianth, solitary or uni- 

 ted on a dilated fleshy receptacle. Seeds pendulous, with or 

 without albumen. Embryo straight, curved or spiral. Ra- 

 dicle superior. 



Stems herbaceous or woody. Leaves alternate or opposite, ge- 

 nerally with stipules. Floivers either in heads or racemes. 

 Mirl. 



1. URTICA. 



Monoecious or dioecious. Barren Fl. Perianth of 4 leaves, 

 containing the cup-shaped rudiments of a germen. Fertile 

 FL Perianth of 2 leaves. Achenium 1 -seeded, shining. 



1. U. wens, leaves opposite elliptical with about 5 ribs, clusters 

 of flowers nearly simple, p. 271. Waste places. 



2. U. dioica, leaves ovate acuminate cordate at the base, clus- 

 ters of flowers much branched in pairs mostly dioecious, p. 27 1 , 

 Hedges. 



2. PARIETARIA. 



Flowers often imperfect, surrounded by a many-cleft involucrum. 

 Perianth 4-cleft. Stam. 4. Filaments at first incurved, then 

 expanding with an elastic force. Ovary 1. Style 1. Ache* 

 rimm 1-seeded, inclosed in the enlarged perianth. 



1. P. officinalis, leaves ovato- lanceolate, involucre of many ovate 

 leaflets, p. 56. Walls. 



3. HUMULUS. 



Dioecious. Barren Fl. Perianth single, 5 -partite. Stam. 5. 

 Anthers with 2 pores at the extremity. Fertile Fl. amenta- 

 ceous. Scales of the catkin large, persistent, concave, entire, 

 single-flowered. Perianth 0. Styles 2. Seed 1. 



1. H. Lupulus. p. 288. Hedges. 



ORDER VI. ARISTOLOCHLE. 



Perianth of 1 piece, adherent. Stam. definite, epigynous. Style 

 simple, very short. Stigma many-lobed in a radiating man- 

 ner. Ovary many-celled. Cells many-seeded. Capsule dry 

 or berried. Seeds very numerous. Embryo very minute, en- 

 tire, at the base of the corneous albumen. Mirb. Br, 



