250 PENNYP ACKER— ON THE BEACH PLUM 



glands on the stipules are very conspicuous, but probably rank second 

 in importance as the stipules are very early deciduous and consequently 

 the glands are seen only for a short time. A reproduction of them is 

 shown in Plate LXVIII, Fig. 11. The glands on the teeth of the lamina 

 are more numerous near the apex of the leaf, and seem to be more com- 

 mon on the young leaves. Many of the older leaves do not show them. 



III. Classification of Varieties 



In deahng with this phase of the subject, I will give a detailed taxo- 

 nomic description of the species as a whole after the style of Sargent. 

 Such a description has not been attempted so far as the present hterature 

 goes and for that reason is needed all the more. Then I will give a de- 

 tailed description of each variety as I have found them. To have estab- 

 lished new species on the basis of the variation presented seemed to me 

 rather to confuse, and for that reason I have decided to describe them 

 as varieties. I might add that some of my varietal characters are equally 

 as strong as the characters which were used in separating P. Gravesii, 

 which grows in the immediate neighborhood and under precisely the 

 same conditions as P. maritima. 



Prunus maritima, Marsh. 

 (Beach Plum) 

 A small slender shrub, occasionally 12 to 15 feet high, with a main 

 stem which is sometimes 3 1/2 inches in diameter, and which divides 

 into numerous erect rigid branches; usually 2 to 5 feet high, erect or 

 prostrate, forming dense thicket like clumps. The bark of the trunk 

 is dark brown to gray, 1/8 to 1/4 inches thick, the fissured surface 

 being broken into thin persistent scales. The branches are stout, rigid, 

 marked with minute pale lenticels, puberulous during the first summer, 

 and unarmed with occasional lateral spinescent or spur-like branchlets. 

 The winter buds are about 1/8 inch long, obtuse, and covered with chest- 

 nut brown scales. The leaves are oval, ovate or obovate, 4.0 to 6.8 

 cms. long by 2.0 to 3.5 cms. wide, on short, stout pubescent petioles, 

 7 to 12 mm. long; acute, finely and sharply serrate with glandular tipped 

 teeth when young; at the base of the blade are two, occasionally one, 

 rather large, round, stalked, dark glands, sometimes eglandular; slightly 

 puberulous to glabrous on the upper surface, while on the lower surface 

 quite pubescent along the midrib and in the axils of the primary veins, 

 slightly along the cross veins of certain varieties. Stipules linear, lobed, 

 pubescent, glandular serrate and very early deciduous. 



