482 ROSACEAE (ROSE FAMILY) 



* * Style / I'niiii'il ; flnirci-K xtna.1l; petals yellow. 



1- Annual or biennial ; leaflets incisely serrate, not white-tomentose : stamens 



5-20. 



2. P. monspeliensis L. Stout, erect, hirsute, 2-1) dm. high ; leaves 3-folio- 

 late; leaflets obovate to oblanceolate, those of the uppermost leaves toothed 

 nearly the whole length ; cyme rather close, leafy ; calyx large ; stamens 15-20. 

 Open soil, Nfd. to Alaska, s. to D. C., Mo., Kan., and N. Mex. May-Aug. 

 (E. Asia.) 



Var. norvSgica (L.) Rydb. Less hirsute ; leaflets more narrowly oblong, 

 those of the uppermost leaves mostly 3-5-toothed near the end ; inflorescence 

 looser. (P. norvegica L.) Similar situations, e. Que. to n. N. E., L. Superior, 

 and northwestw.; occasional on ballast southw. (Eurasia.) 



Var. Iabrad6rica (Lehm.) Fernald. Low (1-3 dm. high, in exposed situations 

 acaulescent) ; stem glabrous or sparingly silky-villous ; leaves smoothish. Lab. 

 to the alpine regions of the White Mts., N. H. 



3. P. rivalis Nutt. More slender and branched, softly villous ; leaves pin- 

 nate, with two pairs of closely approximate leaflets, or a single pair and the 

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

 diffuse, less leafy; calyx small; petals minute; stamens 10-20 (rarely 5). 

 Neb. to Mo., N. Mex., and westw. May-Aug. 



Var. millegrana (Engelm.) Wats. Leaves all 3-foliolate ; lateral leaflets not 

 divided ; stems erect, or weak and ascending ; achenes often small and light- 

 colored. (P. leucocarpa Rydb.) Minn, to Mo., westw. and south westw. 



Var. pentandra (Engelm.) Wats. Leaves digitately 3-foliolate, the lateral 

 leaflets of the lower leaves parted nearly to the base ; stamens 5, opposite the 

 sepals. (P. pentandra Engelm.) Minn, to Mo. and Ark. 



4. P. parad6xa Nutt. Stems decumbent at base or erect, often stout, leafy, 

 subvillous ; leaflets pinnately 5-11, obovate or oblong; cyme loose, leaf y ; stamens 

 20; achenes strongly gibbous on the ventral side. (P. supina of auth., not 

 L.) Prairies and river banks, w. N. Y. and Ont. to 111., Mo., N. Mex., and 

 B. C. June-Aug. (Asia.) 



6. P. Nicolletii (Wats.) Sheldon. Slender; leaflets mostly 3 ; inflorwi-urr 

 much elongated, leafy, falsely racemose. (P. supina, var. Wats.) Sandy soil, 

 Mo. (Bitsh) to N. Dak. 



-- *- Herbaceous perennials, more or less white-tomentose; leaflets inriwlt/ 

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



0. P. pennsylvanica L. Stems erect or decumbent at base, 2-6 dm. high ; 

 leaflets 5-9, white-tomentose beneath, short-pubescent and greener above, ob- 

 long, obtuse, the linear segments slightly or not at all r e volute ; cyme fastigi- 

 ate but rather open. (P. litoralis Rydb.) Coast of N. H., Me., and the lower 

 St. Lawrence, L. Superior, and westw. June-Aug. 



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



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

 rather large yellow petals. 



t- Leaves palmate. 

 w. Flowers in loose leafy cymes. 



7. P. arg6ntea L. (SILVERY C.) Stems ascending or depressed, 1-5 dm. 

 long, paniculately branched at the summit, many-flowered, white-woolly; leaf- 

 lets .",. wedge-oblong, almost pinnatifid, entire toward the base, with iwolute 

 margins, green above, white with silvery wool beneath; calyjr -hit< -tAmni- 

 tose. Dry barren lields, etc., N. S. to Dak. and southw. to I). (\ June- 

 Sept. (En.) 



8. P. ivi i i:\ii;i>iA L. Coarser ; the stout upright {jraiii*h-t>imi-ntulnm- >//> 

 3-7 dm. high: leaflets 3-5, the lateral and often the terminal ck-t-plv cleft. 

 oblanceolate to narrowly obovate, coarsely dentate, green above, grayiah-villoua 

 and tomentulose beneath; cyme somewhat leafy and diffuse; calyx 



