Shrub low, slender, attaining a height of four feet; main trunk much branched, with dark, rough bark; branches ascending, slender, leafless, unarmed; branchlets of the season puberulent. Leaves oval-orbicular, orbicular or slightly obovate, rounded, retuse or apiculated at the apex, base truncate or at least obtuse, margins sharply serrate or crenate-serrate; upper surface sparingly pubescent or glabrous, lower surface pubescent, especially on the veins. Flowers white, one-half inch broad; borne in two or three-flowered, lateral umbels, appearing with the leaves; calyx-tube campanulate, pubescent; petals sub-orbicular, abruptly narrowed at the base; pedicels stout, stiff, pubescent. Fruit maturing in September; globose, one-half inch in diameter, nearly black, with a light bloom, acid and astringent; stone broadly oval, rounded at the apex, acute at the base. _Prunus gravesii_ is now known only in Connecticut, where it is found on a gravelly ridge at Groton near Long Island Sound. It grows in the neighborhood of _Prunus maritima_ to which it is evidently closely related. Small in describing the species gives the following differences between the Gravesii and the Maritima plums: (1) _Prunus gravesii_ is more slender and delicate in habit, and matures its leaves and fruit earlier in the season. (2) The leaf of _Prunus gravesii_ is small and sub-orbicular while that of the other is larger and more elongated. (3) The new species has smaller flowers with sub-orbicular petals while those of _Prunus maritima_ are broadly obovate and gradually narrowed at the base. (4) The fruit of _Prunus gravesii_ is smaller and more globose and has shorter pedicels. (5) The stone is more turgid and is pointed only at the base; that of _Prunus maritima_ is usually pointed at both ends. (6) Sprouts arising from the ground do not produce flowers as they frequently do in the case of _Prunus maritima_. The cultivation of this plum has not been attempted and as compared with Maritima it promises little for the fruit-grower. =22.= =PRUNUS ORTHOSEPALA= Koehne =1.= Koehne _Deut. Dend._ 311. 1893. =2.= Sargent _Gar. and For._ =7=:184, 187 fig. 1894. =3.= Bailey _Cyc. Am. Hort._ 1450. 1901. Shrub four or five feet high; branches dense and twiggy; stems sometimes armed with slender spines; bark separating in large, loose scales; branchlets stout, slightly zigzag, reddish-brown becoming dark brown.