black instead ol" red fruit. Pvostriition has leaf-bearing flower 

 l)U(ls, leaves with sharply acute to acuminate, serrate-dentate 

 lobes, flowers with calyx lobes smooth, about 2 mm. in length, 

 and ol)ovate-oblong in outline, petals Avith rhombic blade on a 

 rather broad stalk, the whole much longer than broad, and fruit 

 red. From hi.i'iformn our new species may be distinguished by 

 the lack of bloom on the fruit, by its usually blunter leaf-lobes 

 and teeth, the scattered glanduliferous hairs on the calyx lobes, 

 and the petals nearly twice as broad as high. Ln.i'iflorum has 

 its fruit black with a bloom, leaf lobes usually acute, no gland- 

 ular hairs on the calyx lobes, and petals commonly a little 

 longer and a little narrower than those of colorddense., therefore 

 only slightly broader than long. 



The s])ecimens of cnjoridlcnsf consulted are as follows: . 



Colorado: 



"Rocky Mountains," (rtori/r Vnxei/, ] 808. 



Mosquito pass, near Leadville, alt. lU.UOO to 11,000 feet, 

 Jnlni Wolf, 1873. 



Marshall Pass, alt. about 10,000 feet, C. L. She((i\ 181)6 

 (Xo. Ho(>). 



"•Southwestern Colorado," [T^a Plata Mountains ?] Slide 

 Rock Canyon, alt. 10,500 feet, B<ihei\ EarJc, and 

 Tracy, 1898 (No. 289). 



San Miguel County, near Telluride, on the headwaters of 

 San Miguel River, alt. 10,000 feet, Fr<nik Tweedy, 

 1894 (No. 190). 



These three species, /irosf/u/fio/i, hi.i'ifjorxni, and colorddense, 

 are very closely related and form a group which might be called, 

 after the ])ractice of the zoologists, a superspecies, or after the 

 practice of some European botanists, a species collective. They 

 differ in minor but well-deflned characters, apparently do not 

 intergrade, and each has a characteristic range distinct from 

 that of the other two. Prostrdtvm centers in eastern Canada, 

 extending across the Great Lake g,nd St. Lawrence region into 

 the LTnited States, continuing southward in the Appalachian 

 district to North Carolina and westward in British America to 

 Manitoba, Saskatchewan, Athabasca, and Mackenzie, and sjieci- 



