616 



BOTANY 



PART II 



Order 4. Urtieinae 



Herbaceous or woody plants with small, inconspicuous flowers 

 closely aggregated in the inflorescence. 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, 

 pendulous ovule. Fruit, a nut or drupe. Seeds 

 usually containing endosperm. 



Family 1. Ulmaceae. Ulmus campestris (Fig. 

 613), the Elm, is a common European tree. The 

 arrangement of the leaves on the sides of the twigs 

 in two rows and the corresponding branching leads to 

 the leaf surface exposed on each lateral branch making 

 a definite angle with the main branch and composing 

 the regular convex crown of foliage exhibited by older 



H 



FIG. 611. Salix viminalis. A, 

 Flowering male twig (nat. size). 

 B, Male flower with subtending 

 bract (magnified). C, Female 

 inflorescence. D - E, Female 

 flowers (magnified). F, Fruit 

 (nat. size). G, The same mag- 

 nified. H, Seed (magnified). 

 (After SCHTMPER.) 



Fiu. 612. Populns iiigra. 1, Male infloi'escence. #, Female 

 inflorescence. 3, Male flower, k, Female flower. 5, Fruit. 

 , Seed. (1, 2, | nat. size ; 3-6, enlarged.) 



examples. The leaves are always asymmetrical The flowers stand in groups in 

 the axils of the leaves of the previous year ; they are hermaphrodite or, by 

 abortion, unisexual. The stamens are straight in the bud. The tree flowers 

 in February or March and the fruits ripen before the leaves expand. The fruits 



