248 WOODY PLANTS OF MASSACHUSETTS. 
tree is of equally rapid growth, and taller and more shapely. 
It has been extensively introduced in England and France, 
where it is valued for its beauty and for its wood. Loudon says 
that the fine poplar avenues in the lower part of the garden of 
Versailles, are of this species. In England, it is called the Can- 
ada poplar, in France, cotton wood. 
Dr. Barratt, of Middletown, Conn., has very kindly communi- 
cated some very interesting and valuable observations, which 
he has made in reference to this poplar and others of the genus, 
together with some striking conclusions as to climate, which he 
has drawn from the times of flowering of several of the trees. 
I give them nearly in his own words. 
The aments of P. levigaia are encased, during the winter 
and early spring, in buds with resinous scales. When the 
aments begin to protrude, these scales expand, nearly in oppo- 
site directions, and soon fall. This is about April 9th, and by 
the 18th, they are in full flower. The aments are first of a 
rose color, and in great abundance, especially on the upper part 
of the tree. This monarch of the Amentacea then presents a 
noble and cheering sight; and is in a high degree ornamental. 
As soon as the pollen is shed, which is in two days from the 
time of the full expansion of the flowers, the rich red pollen 
cells become pale and shriveled, and the sterile aments are soon 
scattered in the wind. These aments are from four to five 
inches long, and have from seventy to one hundred stamens 
resting on each turbinate scale, and of these scales or clusters 
of stamens, each ament has sixty or eighty. The carpels, or 
mature ovaries of the fertile aments, are smooth and ovate, and 
become ripe about the 18th of June, just two months from the 
expansion of the flowers. ‘This fact is the more remarkable, as 
it is just twice the period of the willows. When the carpels of 
the poplar are fully open, the cotton adhering to the seeds is 
shed, and gives the appearance of finely carded cotton, profusc- 
ly spread among the foliage. Hence the name cotion tree, and 
we have thus this southern material produced in Massachusetts 
by a forest tree. 
The other poplars take nearly the same length of time to 
bring their fruit to perfection. In 1839, which was an aver- 
