226 ASPEN: BLACK POPLAR 



to the middle by the gland ; style obsolete, stigmas deeply 

 bind, the 4 greenish arms spreading crosswise. Capsule 

 stalked, pale brown, glabrous, with reflexed valves. 



[The variety canescens has the catkins denser; scales 

 obovate-cuneate, more irregularly incised and ciliate 

 anteriorly, bright brown. Stigmas red or greenish.] 



tt Catkins 25 50 mm. long, scales laciniate: 

 stigmas more deeply cut; leaves glabrous 

 beneath. 



Populus tremula, L. Aspen (Fig. 68). Tree with 

 rounded trembling leaves. 



Catkins sub-sessile, dense and silvery tomentose before 

 anthesis, curved ; pendent and loose and less woolly later ; 

 the </ about 6 10 x 2 cm. ; fruiting catkin up to 12 cm. 

 Scales dark brown, narrow cuneate at the base, with fan- 

 shaped apex deeply incised into narrow teeth, long-ciliate. 

 Disc shortly stalked with oblique mouth, greenish, half- 

 enveloping the stamens and ovary respectively. Stamens 

 4 12; anthers purple-red. Ovary stalked; stigmas 

 purple-red, bifid and the arms radiating crosswise. 

 Capsule distinctly stalked, greenish-brown, valves re- 

 curved. 



** Stamens about 15 30 ; lobes of the 

 stigma short and angular ; catkin-scales 

 glabrous, laciniate ; shoots glabrous, buds 

 viscid. 



t Capsule ovoid, 2-valved. 



Populus nigra, L. Black Poplar (Fig. 69 a). Large 

 tree with dark but open foliage, and deeply coarsely 

 fissured blackish bark. 



Catkins cylindroid and densely-flowered, the <? sessile 



