554 



BOTANY 



TART II 



flowers ; disc cup-sliaped ; no secretion of nectar. The long-stalked circular leaves 

 of the Poplars give them a different habit from the Willows. Flowers similar to 

 tliose of Salix but with divided bracts. Catkins pendulous (Fig. 530). 



Official. — Salicin is obtained from the bark of species o( Salix and Popnliis. 



Pro. 530. — Popnlvs nUjra. 1, Male inflorescence. 2, Female inflorescence. 3, Male flower. 

 A, Female flower. 0, Fruit. G, Seed. (1, 2, | nat. size ; 3-G, enlarged.) 



Opder 5. Urtieinae 



Herbaceous or woody plants with small, inconspicuous flowers 

 closely aggregated in the inflorescence. Mainly anemophilous. 

 Perianth simple, sepaloid. Stamens equal in number to the leaves 

 of the perigone and superposed on the latter. Ovary superior, 

 composed of one or two carpels, usually unilocular, and containing 

 a single ovule. Fruit, a nut or drupe. Seeds usually containing 

 endosperm. 



Family 1. Ulmaceae. — Trees or shrubs with simple, asymmetrical leaves borne 

 in two rows. Tlie pinnate venation, the hairy surface, the serrate margin of the 

 leaf and the caducous stipules are characteristic. Flowers in clusters in the axils 

 of leaves of the jirevious year, hermaphrodite, or unisexual by suppression of the 

 male or female organs. Perigone of 4-6 leaves, with a corresponding number of 

 stamens situated opposite to them. Stamens straight in tlic bud. Unilocular 

 ovary composed of two carpels with one pendulous ovule. Tlie family is widely 

 distributed. 



