POl'ULUS. 



387 



2. PCP'ULTJS Linn. Poplar. 



1. P. al'ba (L.) ; l.-buds downy,!, roundish-cordate angularly 

 toothed cottony and snowy white beneath, 1. of the young shoots 

 cordate palmately 5-lobed, stiff. 2 linear bifid crosslike (yellow). 

 E. B. 1018. With suckers. L. generally lobed. Male cat- 

 kin-scales hairy. Damp woods. T. III. IV. White Poplar. 

 Abele. E. S. 



2. P. canes' cens (Sra.) ; l.-buds downy not viscous, 1. roundish 

 obscurely lobed sparingly cottony and grey beneath, 1. of young 

 shoots cordate-ovate undivided, stiff. 2 wedgeshaped 3 ^-lobed 

 (purple). E. B. 1619. With suckers. L. not lobed, except 

 occasionally the youngest. Male catkin-scales hairy. Damp 

 woods. T. III. IV. Gray Polar. E. 



3. P. trem'ula (L.) ; l.-buds glabrous slightly viscous, 1. nearly 

 round acute serrate glabrous on both sides, young 1. slightly downy, 

 stiff. 2 bifid erect. E. B. 1909. A small tree, with suckers. 

 Petioles laterally compressed. Male catkin-scales hairy, pal- 

 niately cut. Woods. T. IV. Aspen. E. S. I. 



4. P. nigra (L.) ; l.-buds glabrous viscous, 1. triangular-rhom- 

 boidal acuminate serrate glabrous on both sides, catkins lax. cylin- 

 drical, stig. 2 roundish 2-lobed. E. B. 1910. A large tree, 

 without suckers. Petioles laterally compressed. Young shoots 

 glabrous. -Male catkin-scales glabrous. Damp places and river- 

 banks. T. III. Black Poplar. E. 



