CANADIAN POPLAR 229 



Ovary ovoid-conic, glabrous, green, with 4 longitudinal 

 grooves; the disc reaching more than half-way up. 

 Stigmas 2, sessile, yellow, reflexed, irregularly triangular, 

 more or less 3-lobed. Capsule conoid, smooth, olive, 

 stalked, with two widely divaricating valves. 



tt Capsule 3 4-valve(i, globoid. 



Populus Canadensis, Desf. Canadian Poplar (Fig. 696). 

 Very like P. nig^^a in foliage, but the crown less spreading. 



Catkins glabrous, appearing before the leaves, the (/ 

 sessile and up to 12 x 1'2 cm., the % stalked and loose, 

 5 to 8 cm., in fruit up to 25 cm. long. Scales triangular, 

 yellow, incised above and the teeth running into long 

 purple cilia ; those of the $ catkin very caducous. Sta- 

 mens 20 30 with red anthers. Ovary stalked, turbinate 

 or sub-globoid, with 4 grooves ; stigmas 4 (rarely 3 or 2), 

 sessile, very large and folded and cut into kidney-shaped 

 lobes, and closely reflexed half-way down the ovary, which 

 has 4 placentae. Stigmas yellowish with purple margins. 

 Fruits stalked, distant, and naked owing to the caducous 

 scales : dehiscing normally by 4 valves. 



(ii) Flowers not achlamydeous, but with a 

 greenish perianth ; in catkin-like spikes, 

 which are stiff, spreading or erect dwarf 

 shoots. 



(a) Flowers sessile at the base of leafy dwarf 

 shoots; perianth segments two. Fruit 

 fleshy, orange spotted with dark points: 

 seed one. tipinescent shrub with silvery 

 or bronze hairs ; narrow leaves and no 

 latex. 



Hippophae rhamnoides, L. Sea Buckthorn (Figs. 70, 7 1 ). 



