^6 BULLETIN 1'79, U. S. DEPAKTMEITT OF AGRICULTURE. 



State. It evidently reaches nearly to the coast in the vicinity of 

 Savannah, Ga., but is not found in the Coastal Plain of the Carolinas. 



With the possible exception of Prunus pennsylvanica, P. americana 

 is the most widely distributed of any of the native species, and it 

 appears also to be one of the most variable. In the Eastern States 

 it grows mainly in rich alluvial soils, in the Southern States it is 

 frequently met with in the mountain region, but sometimes occurs 

 in river swamps, while in the prairie States of the Mississippi Valley 

 it is found on bottom lands and sometimes on dry uplands. Toward 

 its western limits it is smaller and often assumes even a shrubhke 

 appearance. Material of the species irom the western portion of its 

 range indicates a form having leaves usually more glabrous and of 

 a lighter green color, with a greater tendency to fold in drying. In 

 the East the calyx lobes are usually glandular and minutely toothed 

 toward the apex, while west of the Mississippi River the calyx lobes 

 are usually, though not always, eglandular and entire. There is also 

 a tendency for the stone in eastern specimens to be shorter in pro- 

 portion to its breadth and more turgid than in western material. 

 There are so many exceptions to the constancy of these characters 

 in a definite geographical region, however, that it seems unwise, and 

 in fact apparently impossible, to distinguish any form, even as a 

 subspecies. In southwestern Missouri a grove was found, the trees 

 of which appeared rather different from others in that vicinity. These 

 trees were 10 to 15 feet high; leaves oval-lanceolate to lanceolate, 5 

 to 7 cm. long, 2 to 3 cm. broad, rather long acuminate at the apex, 

 gradually narrowed toward the base, green and glabrous above, pale 

 and rather loosely pubescent below; flowers about 12 mm. broad, 

 pedicels 6 to 8 mm. long, glabrous, calyx entirely glabrous on the 

 outer surface, tube about 2 mm. long, the oblong lobes about as long, 

 obtuse, ciliate on the margin, eglandular, hairy within, at least 

 toward the base; petals 5 to 6 mm. long, oblong-oval to oblong- 

 cuneate; fruit globose. 



Prunus americana was probably the first American species to 

 be described botanically, for it is apparently included by Plukenet 

 in 1696. It was not named binomially until 1785, when it was 

 described by Marshall. So far as known, no types of Marshall's 

 plants are in existence, but there can be Httle possibility of mistakuig 

 the identity of his species in this case, and his material doubtless 

 came from eastern Pennsylvania. Prunus latifolia was described by 

 Moench in the same year in which Marshall's Arbustrum was pub- 

 lished. Moench described his species from material grown from seed 

 obtained in America. P. Tiiemalis was described from "Canada, 

 Virginia et in umbrosis Carohnae." P. ignota, based on specimens 

 collected by C. S. CrandaU on the banks of the Cache la Poudre, 

 near Fort CoUins, Colo., does not differ from the species. 



