Without any first-hand knowledge of this species it is thought best to consider it only under the allied species, Prunus subcordata.
PRUNUS SUBCORDATA KELLOGGII Lemmon
1. Lemmon Pittonia 2:67. 1890. 2. Wickson Calif. Fr. Ed. 2:51. 1891. 3. Greene Fl. Francis 1:50. 1891. 4. Bailey Cyc. Am. Hort. 1448. 1901.
Prunus subcordata kelloggii, named in honor of Dr. Albert Kellogg, an early explorer and settler in California, is distinguished from the species in being a somewhat taller and more slender plant.[130] The branches and bark are of a characteristic ash-gray, so distinct in color from Prunus subcordata that this is often called the “Gray-branch” plum. The leaves are orbicular or elliptical, not cordate, cuneate at the base and nearly glabrous. The fruit is bright yellow instead of red and larger than that of the species, being an inch or more in diameter with a more nearly free stone. This plum inhabits the region of Mount Shasta where it has been known since the time of the early gold diggers, attracting more attention as a food, and promising more for the cultivator than Subcordata. Botanists seem to have given this plum comparatively little attention and careful study may give it specific rank. Locally, and now somewhat in the trade, it is known as the Sisson plum, after a Mr. Sisson, living near Mount Shasta, who has brought it to notice. At present the Kelloggii seems to be the branch of promise for the improvement of the wild plums of the western coast.
15. PRUNUS UMBELLATA Elliott
1. Elliott Sk. Bot. S. C. and Ga. 1:541. 1821. 2. Sargent 10th Cen. U. S. 9:67. 1883. 3. Ibid. Sil. N. Am. 4:33. Pl. 155. 1892. 4. Waugh Plum Cult. 91. 1901. 5. Mohr Cont. U. S. Nat. Herb. 6:551. 1901.
Cerasus umbellata. 6. Torrey and Gray Fl. N. Am. 1:409. 1840.
Tree low, sometimes a shrub, seldom over twenty feet in height; trunk short, usually crooked, attaining a thickness of ten inches; bark dark brown and scaly; branches spreading, slender, twiggy but spineless; branchlets at first pubescent but becoming glabrous, bright red turning dark brown the second year; lenticels few, oblong, yellowish.
Leaves oblong-ovate, or oblong-obovate to oblong, thin and membranaceous, acute at the apex but usually obtuse or cordate at the base; margins closely and evenly serrate with glandular teeth, upper surface dark green and glabrous, lower surface pale green and more or less pubescent; petioles stout, glabrous or sometimes pubescent; glands usually two, sometimes wanting, large, dark, at the base of the leaf; stipules lanceolate, small, caducous.
Flowers medium in size, appearing before and with the leaves; usually borne in four-flowered umbels; calyx-tube obconic, its lobes entire, outer surface glabrous or pubescent, the inner densely tomentose; petals white, orbicular, clawed.