SALICACE^, CONIFERS 130 



2. POP'ULUS, Tourn. POPLAR. 



1. P. tremuloi'des, Michx. (AMERICAN ASPEN.) A tree 

 with greenish-white bark, and roundish heart-shaped leaves, 

 continually in a state of agitation, due to the lateral compression 

 of the petiole, and the consequent susceptibility of the leaf to 

 the least motion of the air. Teeth of the leaves email. 



2. P. grandidenta'ta, Michx., (LARGE-TOOTHED ASPEN) has 

 roundish ovate leaves with large irregular sinuate teeth. 



3. P. balsamif'era, L. (BALSAM POPLAR.) A tall tree, 

 growing in swamps and along streams ; the large buds varnished 

 wilh resinous matter. Leaves ovate, tapering, finely serrate, 

 whitish beneath. Stamens very numerous. 



4. P. monilif 'era, Ait. (COTTONWOOD. ) A tree with broad 

 deltoid leaves, slightly heart-shaped, serrate with incurved teeth. 

 Young branches slightly angled, at length round. Fertile catkins 

 very long, the scales cut-fringed, not hairy. Along the main 

 line of the Grand Trunk Railway. 



Var. can'dicans, Gray, (BALM OF GILEAD) has broader and 

 more or less heart-shaped leaves. 



SUBCLASS II. GYM'NOSPERMS. 



Ovules and seeds naked (not enclosed in a pericarp), 

 and fertilized by the direct application of the pollen. 

 Represented in Canada by a single Order. 



ORDER LXXXIX. CONIF'ERJE. (PINE FAMILY.) 



Trees or shrubs with resinous juice and mostly monoecious 

 flowers, these in catkins except in the last genus (Taxus), in 

 which the fertile flower is solitary and the fruit berry-like. 

 Leaves awl-shaped or needle-shaped. (See Part I., Cap. xvi., for 

 descriptions of typical plants. ) The Order comprises three well- 

 marked Suborders. 



