ROSACEA 



503 



i'_l^' wide; their petioles slender, vviug-inargined above, sparingly glandular, at 

 first villose, becoming glabrous, ^'-|' long; on vigorous shoots broadly obovate, in- 

 cisely lobed at the broad apex, often deeply divided into lateral lobes, or occasionally 

 Globed, 3'-4:' long and 2'-3' wide. Flowers ^'-^' in diameter, on elongated slender 



pedicels, in broad many-flu wered glabrous corymbs; calyx-tube broadly obconic, 

 glabrous, the lobes gradually narrowed from the broad base, acute or acuminate, 

 usually glandular-serrate above the middle, glabrous on the outer, villose on the 

 inner surface, often tinged with red or purple; stamens 20; anthers small, pale yel- 

 low; styles 2-5, surrounded at the base by tufts of long pale hairs. Fruit ripening 

 and falliug in August and September, on slender pedicels, in compact, many-fruited 

 drooping clusters, short-oblong, truncate at the apex, black and lustrous, about -^' 

 long; calyx deciduous, leaving a broad deep cavity; flesh thick, sweet, light yellow; 

 nutlets 3-5, ^ long, narrowed at the base, full and rounded at the apex, ridged on 

 the back, with a narrow ridge, the ventral cavities small and shallow. 



A tree, 30-40 high, with a long trunk 18'-20' in diameter, stout branches 

 spreading and ascending and forming a compact round-topped head, and slender 

 rigid glabrous bright red lustrous branchlets unarmed, or armed with straight or 

 slightly curved blunt or acute bright red ultimately ashy gray spines f'-l' long; or 

 often shrubby, and spreading into wide thickets. 



Distribution. Banks of mountain streams; valley of the Parsnip River, British 

 Columbia, through Washington and Oregon to the Valley of the Pitt River, Cali- 

 fornia, and eastward in the United States through the northern Rocky Mountain 

 region to the Bighorn Mountains, Wyoming; in northern Michigan (Clifton and 

 Thunder Bay), and on Michipicoten Island, Lake Superior. 



132. Crataegus rivularis, Nutt. 



Leaves lanceolate to narrowly oblong-obovate, acute, acuminate, or abruptly 

 acuminate at the apex, gradually narrowed and concave-cuneate at the long entire 

 base, and very finely crenately serrate above, with glandular teeth, when they unfold 

 tinged with red, villose above and coated below with matted pale hairs, more than 

 half grown when the flowers open late in May and then hairy on the midribs and 

 veins above and pale and glabrous below, and at maturity membranaceous, dull bluish 



