3. Prunus nìgra Aiton. Canada Plum. [Plate 101.] Small trees with the characteristic bark of the genus; twigs smooth; leaves obovate or oval, 5-11 cm. long and 3-6 cm. wide, rounded or somewhat narrowed at the base, abruptly short acuminate toward the apex, smooth or sparsely covered above with a short appressed pubescence, more or less pubescent beneath especially along the veins, usually pubescent on the veins at maturity, margins crenate-serrate, the teeth ending in persistent glands, petioles more or less pubescent on the inner surface, and generally bearing a pair of glands, which number varies from 1 to 3, or sometimes absent; flowers appear in April or May in umbels of 2-3, about 2 cm. in diameter—the largest of the genus in Indiana, calyx smooth, the lobes smooth without and within, except toward the base which is pubescent, the lobes reddish and the margins studded with numerous red glands; fruit ripens in July, globose, red; stone short oval and very flat.
Distribution.—New Brunswick to Massachusetts and west to Minnesota and south to central Indiana. In Indiana it is definitely known only from Wells, Blackford and Marion Counties. No doubt it ranges throughout the northern part of Indiana, but it has not been separated from Prunus americana. Higley and Raddin[53] in 1891, when our text books did not separate this species, in a flora which included a part of Lake County Indiana, remark: "There are two distinct forms of Prunus americana; one with slender branches and large flowers with glandular calyx, found in swamps and another found with stout branches and much smaller flowers with the calyx less glandular, grows in dry soil." This no doubt refers to the species under discussion.
In 1898 the author found this species growing in a swamp in Wells County, and transplanted a specimen to high ground in his orchard. It has persisted ever since, growing vigorously and freely suckering from the roots, but it has been quite susceptible to the San Jose scale.
4. Prunus hortulàna Bailey. Wild Goose Plum. [Plate 102.] Small trees with bark exfoliating in plates or rolls on old trees; twigs smooth; leaves oblong-oval, oval, slightly ovate or obovate, generally 6-11 cm. long and 2.5-5.5 cm. wide, rounded and often slightly oblique at the base, acuminate at the apex, margins finely serrated with short rounded and glandular teeth, generally glossy and smooth above, more or less pubescent all over beneath with long hairs, the midrib and lateral veins usually prominent below, petioles pubescent on the inner face and usually bearing one or more glands; flowers appear with the leaves in April or May in umbels of 2-4; calyx glabrous, the lobes glabrous on the outer face, and more or less pubescent within, margins glandular; fruit ripens in August, generally globose, red; stone generally short oval, very turgid, face reticulated.
PRUNUS HORTULANA Bailey. Wild Goose Plum. (× 1/2.)
Distribution.—Central Kentucky northwestward to central Iowa and southwestward to Kansas and east to northwest Tennessee. In Indiana the specimens at hand show it to be confined to the southwestern part of the State, although Pepoon[54] reports a single tree found near Dune Park in Porter County. It is found on sandy roadside cuts, base of sandy wooded slopes, etc., and is a common tree in Sullivan County for miles on the wooded bank of the terrace of the Wabash River.