ROSACEA. (ROSE FAMILY.) 159 



cyme strict and rather close ; stamens mostly 30, on a thick glandular disk. — 

 Rocky hills, N. Brunswick to N. J., Minn., Kan., and westward 



* * Stijle terminal; Jloioers small, yellow ; leaves pinnate or ternate. 

 •f- Annual or biennial ; leaflets incisely serrate, not white-tomentose ; stamens 5 - 20. 



2. P. Worvegica, L, Stout, erect, hirsute (^-2° high); leaves ternate; 

 leaflets obovate or oblong-lanceolate ; cyme rather close, leafy ; calyx large ; 

 stamens 15 (rarely 20). — Lab. to N. J., west to Minn, and Kan. (Eu.) 



3. P. rivalis, Nutt. Moi-e slender and branched, softly villous; leaves 

 pinnate, ivith tivo pairs of closely approximate leaflets, or a single pair and the 

 terminal leaflet 3-parted ; leaflets cuneate-obovate or -oblong; cyme loose, often 

 difl'use, less lesiiy ; calyx small; petals minute; stamens 10-20 (rarely 5). — 

 Neb. to Mo. and N. Mex., and westward. 



Var. millegr^na, Watson. Leaves all ternate ; stems erect, or weak and 

 ascending ; achenes often small and light-colored. — Minn, to Mo., N. Mex., 

 and westward. 



Var. pentandra, Watson. Leaves ternate, the lateral leaflets of the lower 

 leaves parted nearly to the base ; stamens .5, opposite to the sepals. — Iowa, 

 Mo., and Ark. 



4. P. supina, L. Stems decumbent at base or erect, often stout, leafy, 

 suhriUous; leaflets pinnately .5-11, obovate or oblong; cyme loose, leafy ; sta^ 

 mens 20; achenes strongly gibbous on the ventral side. (P. paradoxa, Nutt.) — ■ 

 Minn, to Mo., and westward ; also eastward along the Great Lakes. — Var. 

 NicoLLETii, Watson. Slender; leaflets mostly but 3; inflorescence much 

 elongated, leafy, and falsely racemose. — Devil's Lake, Minn. 



H- H- Herbaceous perennials, more or less white-tomentose ; leaflets incisely pin- 

 natifid ; bractlets and sepals nearly equal; stamens 20-25. 



5. P. Pennsylvaniea, L. Stems erect or decumbent at base (^-2® 

 high) ; leaflets 5 - 9, white-tomentose beneath, short-pubescent and greener 

 above, oblong, obtuse, the linear segments slightly or not at all revolute ; 

 cyme fastigiate but rather open. — Coast of Maine, N. H., and the lower St. 

 Lawrence, L. Superior, and westward. July, Aug. — Var. strig6sa, Lehm. 

 Stems 6-12' high ; silky-tomentose throughout ; leaflets deeply pinnatifid. the 

 margins of the narrow lobes revolute ; cyme short and close. — Minn, and 

 westward. 



§ 2. Styles filiform, not glandular at base ; inflorescence cymose. 

 * Style terminal; achenes glabrous; stamens 20; herbaceous perennials, with 



rather large yellow flowers. 

 H- Leaves pinnate. 



6. P. Hippi^na, Lehm. Densely white-tomentose and silky throughout, 

 the upper surface of the leaves a little darker; stems ascending (1 - 1^^° high), 

 slender, branching above into a diffuse cyme; leaflets 5-11, cuneate-oblong, 

 incisely toothed at least toward the apex, diminishing uniformly down the petiole ; 

 c;arpels 10-30. — N. W. Minn., and westward. 



7. P. efiusa, Dougl. Tomentose throughout, with scattered villous hairs ; 

 stems ascending (4-12' high), diffusely branched above ; leaflets 5-11, inter- 

 ruptedly pinnate, the alternate ones smaller, cuneate-oblong, coarsely-incised-ser- 

 rate or dentate; carpels 10. — W. Minn, to Mont, and Col. 



