52 BULLETIN 179, V. S. DEPARTMENT OF AGRICULTURE. 



Type specimens in the economic collection of the United States 

 Department of Agriculture were collected, flowers, May, 1910, by 

 O. F. Barnes, about 10 miles northeast of Roscommon, foliage and 

 fruit September 23, 1910, by W. F. Wight, No. 4698, about 4 miles 

 south of Houghton Lake, Mich. Attention was first called to this 

 plum by C. A. Davis, of the United States Geological Survey, who 

 had observed a blue-fruited plum of the maritima type growing along 

 the gravelly ridges in the region south of Houghton Lake. Mr. 

 Davis beheved it would be found to be an undescribed species, and 

 it is accordingly named for him. It differs from the species mainly 

 in its leaves, which are broader in proportion to their length and less 

 acuminate toward the apex. It may be distinguished from Prunus 

 maritima by the reddish color of the young twigs, the more glabrous 

 leaves, glabrous pedicels, and by the stone being pointed instead of 

 rounded at the base. 



The fruit is used locally in making jellies and conserves. 



Prunus Umbellata Elliott. 



(Sloe.) 



Prunus umbellata Elliott, 1816, Sketch Bot. S. C. and Ga., v. 1, p. 541. 



Leaves lanceolate, oblong-lanceolate or oval (PI. V, fig. 4), 4 to 7 

 cm. long, 1.2 to 3 cm. broad, in age becoming rather firm in texture, 

 narrowed or rarely rounded at the base, usually acute at the apex, 

 the margin finely serrate with acute, incurved, rarely gland-tipped 

 teeth, glabrous above, usually pubescent below along the midrib, 

 and sometimes also along the lateral veins and the margin of the 

 blade toward the base, marked with one or two glands near the base 

 of the blade or toward the apex of the petiole, or eglandular; petioles 

 mostly 5 to 7 mm. long, pubescent, at least along the upper surface. 

 Flowers 10 to 18 mm. broad, appearing before the leaves the last of 

 February or in March, in umbels of 2 to 4 ; pedicels 8 to 10 mm. long, 

 slender and glabrous; calyx tube narrowly obconic, glabrous, about 

 3 mm. long, the ovate, obtuse lobes 1.5 to 2 mm. long, very obscurely 

 hairy without, more strongly pubescent within, entire or minutely 

 toothed at the apex, mainly erect at anthesis; petals oblong-obovate 

 to nearly orbicular, 4 to 6 mm. long. Fruit globose, about 12 to 20 

 mm. in diameter, red, yeUow, or more often dark purple when fuUy 

 ripe, and covered with a glaucous bloom, ripening from the last of 

 July to September; stone oval or nearly globose (PI. XII, figs. 7 to 13)^. 

 about 11.5 to 15 mm. long, 8.5 to 11 nun. broad, 6.5 to 8 mm. thick, 

 obtuse or sometimes sHghtly pointed at the ends, variously grooved 

 near the ventral and usually along the dorsal edge, the surface smooth 

 or reticulate. 



