=1.= Marshall _Arbust. Am._ 112. 1785. =2.= Wangenheim _Amer._ 103. 1787. =3.= Michaux _Fl. Bor. Am._ =1=:284. 1803. =4.= Pursh _Fl. Am. Sept._ 332. 1814. =5.= Nuttall _Gen. N. Am. Pl._ =1=:302. 1818. =6.= Elliott _Sk. Bot. S. C. and Ga._ =1=:543. 1821. =7.= Torrey and Gray _Fl. N. Am._ =1=:408. 1840. =8.= Torrey _Fl. N. Y._ =1=:194. 1843. =9.= Emerson _Trees of Mass._ 449. 1846. =10.= Bailey _Cornell Sta. Bul._ =38=:75, fig. No. 9. 1892. =11.= Waugh _Vt. Sta. An. Rpt._ =12=:234. 1899. =12.= Bailey _Cyc. Am. Hort._ 1449, fig. 1901. _P. littoralis._ =13.= Bigelow _Fl. Bost._ Ed. =2=:193. 1824. _P. pubescens._ =14.= Torrey _Fl. U. S._ 469. 1824. _Cerasus pubescens._ =15.= Seringe _DC. Prodr._ =2=:538. 1825. =16.= _Beck Bot. Nor. and Mid. U. S._ 96. 1833. Shrub four to ten feet high, sometimes a low tree under cultivation; main branches decumbent and straggling or upright and stout; bark dark brown or reddish, more or less spiny, often warty; branchlets slightly pubescent at first, becoming glabrous, dark reddish-brown, straight or slightly zigzag and rather slender; lenticels few, small, dark. Winter-buds small, long, acute, with small reddish scales; leaves oval or obovate, short-acute or nearly obtuse at the apex, rounded or nearly acute at the base, margins closely and evenly serrate, thinnish or thickish and somewhat leathery; upper surface glabrous, dull green, lower surface paler and more or less pubescent; petioles less than one-half inch long, stout, tomentose or glabrous; glands two, sometimes more, at the base of the leaves. Flowers small, appearing before the leaves but the latest of any of the hardy plums; borne in three-flowered umbels closely set along the rigid branches; calyx-tube campanulate, tomentose; petals white, sometimes pinkish, sub-orbicular, narrowed into a claw at the base; pedicels short, slender, stiff, tomentose. Fruit maturing in late summer in Massachusetts; one-half inch in diameter, globose, slightly flattened at the ends; cavity shallow, borne on a slender pedicel more than one-half inch in length, usually dark purple with a heavy bloom but variable, sometimes red or less frequently yellow; skin thick, tough and acrid; flesh crisp, juicy, sweetish; stone free from the flesh, small, turgid, pointed at both ends, cherry-like, acutely ridged on one and grooved on the other edge.