202 Rhodora [DECEMBER 
laciniately cleft into 5 or more teeth: staminiferous disk (on a stalk 2 
mm. long) elliptic, about 3 mm. long, 2 mm. broad: stamens 12-16; 
anthers red, 1 mm. long: pollen-grains almost smooth, somewhat 
larger than in P. alba. 
Comparing the descriptions we find several factors which do not 
agree, particularly the number of stamens. In general the floral parts 
in P. canescens exceed in size those of P. alba. Those who are in 
position to observe the two species in the same locality will soon learn 
to distinguish them in flower. The leaves of the young growth and 
root-shoots of P. alba are more or less deeply lobed, while in P. canes- 
cens they are merely toothed, or at the most shallowly lobed. Both 
are known to send out innumerable root-shoots. 
Populus canescens should be included in the list of introduced trees 
that have become established in many places. I have not observed 
it in the North and specimens, collected in New England southward 
to Pennsylvania, belonging to the P. alba group, which have come to 
my notice, have invariably been P. alba. 
PoruLUs ALBA BoLLEANA. This handsome fastigiate form is found 
in cultivation in our region, but not escaped so far as I have been able 
to ascertain. Its floral characters differ somewhat from those of P. 
alba. Stam. aments, fullgrown, about 6 cm. long, 1 em. or less in 
diameter: subtending floral bracts villous, rounded with a cuneate 
stalk equalling the blade; the latter dark brown below, lighter brown 
towards the apex, cleft into 4 nearly equal teeth: staminiferous disk 
(on a stalk 1 mm. long) elliptic about 2 mm. long, 1.5 mm. wide: sta- 
mens 8; anthers red, 1 mm. long. 
POPULUS GRANDIDENTATA. This species was first recorded from 
Canada by Michaux Sr., and the diagnosis by Richard reads: 
* P. petiolis superne compressis; foliis subrotundo-ovalibus, acumi- 
natis, utrinque glabris, inaequaliter sinuato-grandi-dentatis. 
Obs. Affinis P. albae; foliis itidem quandoque basi biglandulosis. 
Hab. in Canada." [L. C. Rich. in] Michx. Fl. Bor. Am. 2: 243, 
1803. 
Later Michaux Jr.' in his illustrated account of the trees of North 
America gives us additional information about it so as to leave us in 
no doubt as to its identity. 
Prior to 1806 Muhlenberg communicated specimens (?) of a poplar 
1Hist. des Arbres For. do l'Amér. Sept. 1812-13. 
