APPENDIX.
387
XL CLASS ICOSANDRIA.
43.  Prunus *incana, L. v. Schw.
Mr. Say calls this shrub a cherry, found at the Lake of the Woods, and from a vestige of an umbell, there is little doubt that it belongs to the genus Prunus, although there is neither flower nor fruit. If so, it is doubtless an undescribed species.
The young branches are very red and angularly grooved; the older gray and verrucose. The leaves alternate, on short petioles, elliptically acuminate, finely and subdistant-ly serrate above, and attenuated into the petiole below, with the margin somewhat revolute. The upper surface smooth and shining, the under pinnately nervose, and remarkably glaucous, a little tomentose. Two large glandules in the axill of each leaf. The traces of a few flowered umbell appear at the commencement of the young branches of the year.
Hab. Islands in the Lake of the Woods.
44.  Aronia sanguinea, Nutt. p. 306. Pyrus sanguinea, Pursh, p. 340.
Destitute of flowers or fruit; but doubtless this Canadian tree.
Hab. Lake of the Woods.
45.  Crataegus elliptica, Pursh, p. 337. Not uncommon.
Hab. near Pembina and Lake of the Woods.
46.  Crataegus *fiexuosa,\t. v. Schw.
Flower and fruit are wanting, but there can be no doubt of the genus from the habit. The leaves greatly resemble those of C. populifolia, although they cannot be said to be at all cordate at base. Perhaps it may be the C. populifolia of Walter, see Elliott, Sketch, I. p. 553. But the re-