76 FIELD AND WOODLAND PLANTS 



very young they are hairy and sticky to the touch ; hence the 

 specific name of glutinosa. The catkins appear before the leaves, 

 and are mature in March or April. The staminate catkins are 

 pendulous, and much like those of the Birch ; but the flowers 

 have red scales and four stamrms. The pistillate catkins are 

 short and erect, and each flower has a fleshy scale within a reddish- 

 brown, woody bract. The fruits are shed in the autumn, but 

 the thickened woody bracts of the female catkin remain on the tree 

 till, and even after, the flowers of the following spring are in bloom. 



Coming now to the order Salicacece, we have to deal with the 

 Poplars, of which we have several species, all more or less 

 common, and largely planted in cultivated ground. Our 

 first example is the White Poplar {^opulus alba), a large tree 

 frequently seen in abundance in most woods. It has a 

 smooth, grey bark, spreading branches, downy shoots and buds, 

 and it throws off many suckers from its roots. The leaves are 

 roundish, approaching a heart-shape, except those of the young 

 shoots, which are divided more or less deeply into five lobes ; and 

 they are covered below by a white cottony down. The flowers 

 are imperfect, and the male and female catkins, produced on different 

 trees, are mature in March or April. The male catkins are three 

 or four inches long, and each flower has from six to ten stamens, 

 with red anthers. The female catkins are much shorter, and its 

 flowers have divided stigmas, with long, narrow, yellow segments 

 arranged like a cross. The ovaries ripen into capsules which split 

 open in July, setting free seeds which are provided with cottony 

 filaments ; and the seeds often fall in such abundance as to almost 

 completely cover the ground beneath the tree. 



The Grey Poplar (P. canescens) grows in similar situations, and 

 flowers at the same time. Its leaves are roundish, with a waved 

 and toothed margin, and are covered beneath with a slight coating 

 of grey down. Those of the youngest shoots are more or less lobed. 

 In this species the two stigmas are purple, wedge-shaped, and 

 divided into from two to four lobes. 



A third species — the Aspen (P. tremula) receives its specific 

 name from the tremulous movements of its leaves, which swing 

 with a rotary movement when disturbed even by the slightest breeze. 

 This characteristic is common, to a greater or lesser degree, to all 

 the species of this genus, and is due to the peculiar nature of the 

 leaf -stalks, which are long, and fiattened in a plane at right angles 

 to that of the blade of the leaf. The Aspen has a grey bark, spreading 



