44 BULLETIN 179, U. S. DEPARTMENT OF AGRICULTURE. 
Prunus ANGUSTIFOLIA Hyprips. 
The early ripening of the fruit of Prunus angustifolia has caused 
it to be used in hybridizing with P. triflora (Pl. XIII, fig. 13, Six 
Weeks) with which it crosses very readily, and it is supposed also to 
be one of the species used in producing the variety Chicrigland. 
This is said to be a combination of P. angustifolia, P. reverchonii, and 
P. texana (P: glandulosa (Hook.) Torr. and Gray). 
Prunus ANGUSTIFOLIA WaTsoni (Sargent) Waugh. 
(Sand plum.) 
Prunus watsoni Sarg., 1894, in Gard. and Forest, v. 7, p. 134, f. 25. 
Prunus angustifolia watsoni Waugh, 1899, in Vt. Agr. Exp. Sta., 12th Ann. Rpt., 239. 
Leaves oval or oblong-oval, 3 to 4.5 em. long, 12 to 18 mm. broad, 
gradually narrowed toward the base, usually acute at the apex, some- 
times abruptly so, lustrous above, pale and glabrous below or some- 
times a few scattered hairs along the midrib toward the base, the 
margin finely crenate and glandular; petioles slender, 6 to 18 mm. 
long, glabrous, or sometimes pubescent along the upper edge. Flowers 
appearing in Kansas from the last of March to about April 20, some- 
times with red anthers, otherwise not differing from the species. Fruit 
very similar to the species, but ripening from the first of August 
to the first of October, or in the Panhandle region early in July; 
stone oval or rarely obovoid, about 13 or 14 mm. long, 9 mm. broad, 
7 mm. thick, truncate or oblique at the base, rounded or pointed 
at the apex, variously grooved on either side of the ventral edge or 
the grooves very obscure but without a winglike margin, grooved 
along the dorsal edge, prolonged at the base when obovoid. 
Prunus angustifolia watson: is usually a shrub 3 to 6 feet high 
with rather stiff branches, these often furnished with spinescent 
branchlets. 
The subspecies was originally described from garden specimens 
grown from seed sent from Ellis, Kans., by Dr. Louis Watson. It 
ranges from northeastern Kansas southwestward through Oklahoma 
and the Panhandle region of Texas to the vicinity of Nara Visa, 
Quay County, in northeastern New Mexico. Its eastern boundary 
is not well defined, but no specimens have been observed east of a 
line drawn from the northeastern part of Kansas southwestward 
to the junction of the North Fork of Red River with the main 
stream, yet it doubtless occurs somewhat farther east. It does 
not appear to have been collected much west of Ellis and Seward 
Counties, in Kansas. It has several times been reported from 
southeastern Nebraska, but no specimens are to be found in the 
larger herbaria from that region, and it probably occurs in Nebraska 
only under cultivation. 
