22 General Key to the Families 



3. R. hudsonianum. Richards. Black Currant. 



4. R. laxiflorum. Pursh. Skunk Currant. 



XXXVII. ROSACES. ROSE FAMILY 



Trees, shrubs or herbs; leaves alternate, simple or compound, 

 mostly foliaceous with stipules; flowers perfect or unisexual, reg- 

 ular in cymes, corymbs, panicles or solitary, with numerous dis- 

 tinct stamens inserted on the calyx, sepals united at the base, often 

 appearing double by a row of bractlets outside; fruit seeds, folli- 

 cles, achenes or drupelets, with little or no albumen. 



TRIBE SPIR^A 



I. SPIRAEA. (Tourn.) L. 



1. S. lucida. Dougl. Birch-leaved Spiraa. 



2. S. densiflora. Nutt. Pink Spircea. 

 II. ARUNCUS. (L.) Adans. 



i. A. Sylvester. (L.) Karst. Goat's Beard. 



III. LUTKEA. Bong. 



i. L. pectinata. (Pursh.) Kuntze. Alpine Spircea. 



TRIBE POMEyE 



IV. PYRUS. (Tourn.) L. 



i. P. sambucifolia. C. and S. Western Mountain Ash. 

 V. AMELANCHIER. Medic. 



1. A. florida. Lind. Common Serviceberry. 



2. A. Cusickii. Fernald. Thick-leaved Serviceberry. 



TRIBE POTENTILLE.E 



VI. FRAGARIA. (Tourn.) L. 



1. F. glauca. Wild Strawberry. 



2. F. bracteata. Heller. Wood Strawberry. 

 VII. SIBBALDIA. L. 



i. S. procumbens. L. Creeping Sibbaldia. 



VIII. POTENTILLA. L. 



1. P. Anserina. L. Silver Weed. 



2. P. dissecta. Pursh. Common Cinquefoil. 



3. P. dissecta var. glaucophylla. Smooth Cinquefoil. 



