36 FAMILIAR TREES 



their female catkins lax, their scales almost smooth, 

 and their stamens more than twelve in number ; and 

 they have been accordingly united in the section 

 named Aigei'ros — a name formerly applied to the 

 Black Poplar. It wiU, perhaps, be clearer to give 

 their characters in succinct form. 



POPULUS. — Section I. : Leuce. — Shoots downy ; 

 female catkins dense ; scales ciUate ; stamens four — 

 twelve. 



1. P.. alba L., White Poplar, or Abele : Leaves on 

 the suckers lobed, those on the branches roundly 

 heart-shaped, slightly lobed; white and cottony on 

 the under surface; stigmas two, bifid, linear, cross- 

 like, yeUow. 



2. P. canes'cens Sm., Grey Poplar : Leaves on the 

 suckers angled and toothed, those on the branches 

 roundly heart-shaped, hoary or smooth on the under 

 surface ; stigmas two-, three-, or four-lobed, wedge- 

 shaped, purple ; buds downy. 



3. P. trem'ula L., Aspen: Leaves on very long. stalks, 

 those on the suckers heart-shaped, pointed, not 

 toothed, those on the branches rounded, with incurved 

 teeth, sUky or smooth on the under surface ; stigmas 

 two, bifid, erect ; buds slightly viscid. 



Section II : Aigeiros. — Shoots smooth ; female 

 catkins lax ; scales nearly smooth ; stamens twelve — 

 twenty. 



4 P. nig'ra L., Black Poplar: Leaves on long stalks, 

 when young rhombic in form, silky on the under 

 surface, and ciliate ; when old more rounded finely 

 toothed, smooth; stigmas two, roundish, two-lobed; 

 buds viscid ; no suckers. 



