KEY TO THE SPECIES 37 



lanceolate, entire, silky; flowers numerous, with yellow rounded petals ; achenes 

 densely hairy. Wet grounds. 



6. FRAGARIA (Strawberry) 



Low herbs with runners, a cluster of palmate basal leaves, the 3 leaflets 

 obovate and serrate, the naked stem terminated by a cluster of white flowers which 

 are nearly as in Potentilla, but the receptacle in fruit much enlarged and conical, 

 becoming pulpy and scarlet and bearing the minute dry achenes scattered over 

 its surface. (See Plant Belations, p. 57, Fig. 47.) 



1. Fragaria glauca (.Wats.) Rydb. (Mountain Strawberry). Sparingly 

 appressed-silky ; the leaves thin and glaucous ; leaflets obovate, short petioled, 

 coarsely toothed, the lateral ones oblique at base ; scape few-flowered, about 

 equaling the leaves ; achenes in shallow pits. The most frequent of our wild 

 strawberries. 



2. Fragaria prolifica Baker & Eydb. (Fruitpdl Strawberry). Similar, 

 but with very short thick rootstock, the leaves strongly veined beneath, green and 

 not glaucous ; the runners very numerous and stout ; the obovate petals scarcely 

 exceeding the sepals; fruit large, the achenes in pits. In the Colorado mountains; 

 at higher elevations than the preceding. 



7. ARGENTINA 



Perennial, the leaves interruptedly pinnate ; spreading by runners ; the soli- 

 tary flowers on long peduncles from the axils of the leaves ; petals sub-orbicular ; 

 stamens 30-25 ; styles lateral, slender ; the achenes glabrous. 



1. Argentina Anserina (L.) Rydb. (Silver-weed). Leaflets 7-21, green and 

 glabrate above, silvery-silky beneath ; from oblong to obovate, sharply serrate ; 

 the stipules membranous. 



8. POTENTILLA (Cin(}uefoil. Potentilla) 



Herbs with compound leaves, solitary or clustered flowers, flat 5-cleft calyx 

 with as many bractlets at the intervals, and numerous achenes in a head with the 

 styles not persisting as a tail. (See Plant Relations, p. 79, Fig. 72 ; also Plant 

 Structures, p. 225, Fig. 205.) 



» Leaves pinnate. 



1. Potentilla Flattensis Nutt. (Potentilla of the Valley). Stems 

 spreading or prostrate, 1-2 dm. long ; leaves green, appressed-strigose or glabrate; 

 the stipules large ; leaflets 4-7 pairs, obovate, deeply incised ; petals obovate, 

 refuse, exceeding the long acuminate sepals which exceed the similar bractlets. 

 Frequent on sandy bottom lands. 



2. Potentilla Coloradoensis Rydb. (Colorado Potentilla). Silky tomen- 

 tose throughout ; stems several, about 3 dm. high ; leaflets interruptedly pinnate, 

 4-6 pairs ; cyme branched ; petals obcordate. scarcely longer than the narrow 

 sepals ; carpels 10-20. A copjmon species on dry gravelly hills. 



* * Leaves ternate. 



3. Potentilla Monspeliensis L. (Rough Cinquefoil). Stout, erect, hirsute, 

 2-4 dm. high ; leaves ternate, with obovate or lanceolate serrate leaflets ; small 

 yellow flowers in a rather close leafy cluster, stamens 15 (rarely 20). Open ground. 



* * * Leaves palmately 5-foliatp. 



