ROSACEA. 289 



ing species most resembling Ivesia Gordonii, Torr. & Gray, 1. c, on the 

 one hand, and I. santolinoides, Gray, on the other. Characters of all 

 three are given in the memoir above cited. 



Plate 4. Ivesia Pickeringii: of the natural size. Fig. 1. Portion 

 of a leaf. 2. A flower. 3. Portion of the calyx, with a petal and two 

 stamens. 4. The entire calyx laid open, showing the insertion of 

 the stamens. 5. Pistils. 6. A separate pistil. 7. Ovary laid open 

 longitudinally, showing 9. An achenium. 8. Transverse section of 

 the same. 10. A seed. 11. The embryo. 



9. POTENTILLA, Linn. 



1. POTENTILLA RIVALIS, Nutt. 



Hab. Low grounds, California, Oregon, and Washington Terri- 

 tory. — The var. millegrana, P. millegrana, Dougl. [Confounded with 

 P. Norvegica.~\ 



2. POTENTILLA GRACILIS, Dougl. 



Hab. Nisqually, Puget Sound: the typical plant. Washington 

 Territory and Oregon, in rich soils ; the var. flabelliforrnis (P. flabel- 

 liformis, Lehm.) ; evidently not specifically distinct. 



3. POTENTILLA FRUTICOSA, Linn. 



Hab. Near Fort Colville on the Columbia ; seen nowhere else in 

 Washington Territory or Oregon. 



4. Potentilla Anserina, Linn. 



Hab. San Francisco, California (var. communis) . Puget Sound, in 

 woods (var. grandis). Saline soils between Fort Okanagan and Grand 

 Coule (var. concolor). 



73 



