1911] Bartlett, Populus virginiana and P. angulata 13 
The best account of Populus angulata is that of Michaux f.! Ac- 
cording to his Histoire des Arbres this tree occurs from lower Vir- 
ginia through the Carolinas to Georgia, from the mouth of the Miss- 
issippi to the Missouri, and up the latter river a distance of a hundred 
miles. It is characteristic of the muddy banks of streams which are 
subject to overflow. 
In the region of the lower Mississippi, Populus angulata is associated 
with a similar and very closely related tree which Michaux f. described 
under the name P. canadensis, although it seems not to be the same 
as the P. canadensis of authors earlier than he. Populus angulata, 
the Carolina poplar, and the P. canadensis of Michaux f., the cotton- 
wood of the middle West, differ from P. deltoides and P. virginiana 
in having remarkable cork wings on the twigs and younger branches. 
''hese are arranged in a definite geometrical pattern; — at the inser- 
tion of each petiole one wing runs directly downward, and two others, 
which lie parallel to the first, on either side of it, form an arch with the 
petiole at the apex. Above each petiole (or bud, or twig, as the case 
may be), a cork wing turns obliquely aside and ends abruptly. The 
wings persist on the branches and trunk for several years, until they 
are obliterated by the fissuring of the bark. Michaux states that 
his P. canadensis is rare in the Atlantic states, most common on the 
Mississippi, Arkansas and Missouri Rivers and their affluents. He 
mentions having seen the tree in the East along the Genesee River, 
in New York (specimens more than a meter in diameter), in certain 
parts of Virginia (localities not specified), and notably on many is- 
lands of the Ohio. Michaux says that its ability to withstand intense 
cold proves its distinctness from P. angulata,—a tree so tender 
as to be damaged by frost even in the climate of Paris. Aside from the 
fact that the trees have an entirely different aspect, he says that they 
can easily be told by their buds; those of Populus angulata are short, 
very green, and not aromatic-resinous, as are those of P. canadensis. 
Both plants deserve the attention of botanists. 
The trees of Populus angulata at Augusta have leaves which are 
several times as large as those of P. virginiana,— another character 
which confirms the distinctness of the two. Even P. virginiana 
itself, however, is so little known to our botanists that a new piece 
of evidence that it is distinct from P. deltoides will be of interest. Mr. 
M. A. Carlton, ? in his studies of the rusts of willow and cottonwood, 
1 Histoire des Arbres, iii. pp. 302-305 (1813.) 
2 Bull. 63 Bur. Plant Industry, U. S. Dept. Agric., p. 19 (1904). 
