52 BOTANICAL GAZETTE [JULY 
have gone unquestioned into this group. Wright’s 181 in Plante 
Wrightiane Texano-Neo-Mexicane is referred to P. rivuldaris by Gray," 
who says, however, “verging to P. Americana;” and this specimen in 
the National Herbarium is transferred to P. Americana “ fide Sargent, 
1892,” which shows how equivocal are the current notions of P. 7#0u- 
aris. This is, however, a very interesting and puzzling specimen 
having broad oval leaves, with irregular shallow obtuse obscurely glan- 
dular crenulations. Still another specimen which has sometimes been 
referred to P. rivularis is one collected by J. Wolf in Illinois in 1875 
This is quite doubtful. In the National Herbarium it is marked “P. 
hortulana, fide Sargent, 1892.” The leaves of this are small and 
shining, with a fine downy pubescence on the young twigs and petioles. 
But this pubescent character, which is important in the Wayland group, 
is not at all so marked as among the Wayland varieties proper. Another 
specimen, sometimes named P. rivudaris, is that of Thos. Bassler from 
Manhattan, Kan., 1883. This is a poor specimen, with only flowers 
and twigs, but is unquestionably P. Americana. 
The characters of the Wayland varieties, as well as of the Prunus — 
rivularis material, are such as would suggest hybridity between P. 
angustifolia and P. Americana mollis. Especially the pubescent nature 
of the petioles and of the veins on the backs of the leaves indicates 
the parentage of P. Americana mollis. The general shape of the leaves 
and the character of the serratures also point in the same direction. 
As already pointed out, the distribution of the Wayland varieties 
almost exactly corresponds to the joint distribution of P. angustifolia 
and P. Americana mollis. T.V. Munson, in private correspondence — 
assures me that, in extensive travels through western Texas, he has 
quite uniformly found an abundance of Scheele’s P. rivularis, te 
plums of the Wayland class; and, distributed everywhere with these, 
Fa australis (P. Americana mollis) and P. angustifolia. He writes Me ; 
also that he has grown hundreds of seedlings from this wild stock 
along with the cultivated varieties and their seedlings, and that the 
group is quite homogeneous and distinct. = 
Thus it seems probable that Scheele, who, perhaps, had no personal 
acquaintance with plums in America, and who had a comparatively 
small amount of material in Lindheimer’s 389, gave specific rank to 
group which American botanists would not have mentioned separately 
and which American horticulturists would have classified immediately 
** Pl. Wright. Tex.-Neo-Mex. 67. 1850, 
