388 



GENERAL BOTANY 



Reproduction. The flowers of the willows occur in the form of 

 catkins (Fig. 240), which are a modified form of a spike in which 

 the bracts are represented by conspicuous scales. The catkins of 

 the pussy willow (Salix discolor) are thick and oval and have 

 received the name pussy on account of the silky hairs that clothe . 



the young catkins 

 in early' spring. 

 Since these cat- 

 kins are borne 

 on separate trees, 

 the willows are 

 dioecious and are 

 entomophilous, or 

 cross-pollinated by 

 the insects which 

 visit the flowers 

 for the nectar 

 secreted by nec- 

 tar glands at the 



Female flower base of the flow- 

 Fewle "catkin ^ The ^^ 



is -abundant and 

 sticky, so that 

 frequent pollina- 

 tion is assured 

 although the flow- 

 ers occur early 

 in the spring. 



The individual flowers are very simple, the females consisting of 

 a simple compound ovary composed of two sporophylls subtended 

 by a hairy bract. The male flowers bear two or more stamens, 

 according to the species, in the axil of a hairy bract (Fig. 240). 

 The fruit is a capsule, or pod, and the seeds ripen early in the 

 spring, after fertilization. The two sporophylls comprising the 

 fruit separate so as to liberate the seeds when they are ripe. 

 The long, silky hairs of the seeds facilitate their distribution 

 by the wind, or by water currents. 



Seed 



Female catkin 

 (fruiting stage) 



Fruit 



Fruit opening 

 (dehiscence) 



FIG. 240. Inflorescence, flowers, and fruit of willow 



