JOHNSON: A REVISION OF THE SECTION BORAPHILA 35 



on the west coast of Alaska, from Point Barrow southward, including 

 the islands of Bering Sea. S. rhomboidea inhabits the higher elevations of 

 the Rocky Mountains, from southeastern British Columbia to central New 

 Mexico. Specimens of it have also been examined from a few scattering 

 stations in the Cascade Mountains of Washington and Oregon and the 

 Sierras of California. S. franciscana is restricted to the San Francisco 

 Mountains of Arizona. It somewhat resembles reduced forms of 5". rhom- 

 boidea of which it is probably an offshoot. 



The few species represented in the section can be readily separated 

 into two categories on characters of the inflorescence, and also on the color 

 of the petals. Thus we obtain one group with a capitate inflorescence and 

 white petals, which includes S. rhomboidea and 5. franciscana, two rather 

 closely related species. The second group is represented by the single 

 species 5*. hieracifolia which possesses a spicate inflorescence and purple 

 petals. The two first named species are separated on the characters of the 

 carpels and the beaks. The differences in the inflorescences are quite obvi- 

 ous, although in reduced forms oi S. hieracifolia where only a few flowers 

 are present the inflorescence is capitate. 



Key to the Species 



I. Inflorescence capitate ; petals white 



1. Follicles stout ; beaks erect or spreading S. rhomboidea 



2. Follicles small ; beaks slender, strongly divergent 5. franciscana 



II. Inflorescence spicate, occasionally capitate; petals purple S. hieracifolia 



Saxifraga rhomboidea Greene, Pittl. 3:3.53. 1896-1898. 



Saxifraga interrupta Greene, Plantae Bakerianae. (Unverified.) 



Saxifraga rhomboidea austrina A. Nelson, Bot. Gaz. 31 :394. 1901. 



Micranthes rhomboidea (Greene) Small, N. Am. FI. 22:2:136. 1905. 



Saxifraga nivalis Hook., Fl. Bor. Am. 1:248. 1832; in part; not 5". 

 nivalis L. 



Specimens of this species have been frequently referred to Saxifraga 

 nivalis L., from which it differs, however, both in general appearance and 

 in floral characters. The inflorescence of ^. nivalis is distinctly corymbose 

 rather than capitate, the leaves are broadly ovate rather than oblong-ovate, 

 and the gland is a thick, fleshy, lobed ring raised above the base of the 

 calyx. 5". nivalis is also typically a much smaller plant than S. rhomboidea 

 (Plates X, XI). Differences in the glands of the hairs will also be noted 

 on comparing the plates referred to. 



Distribution. — Rocky Mountains from British Columbia and Alberta to New 

 Mexico, and in the Cascade Mountains, and the Sierra Nevada. 



Specimens examined : 



Alaska: Shumagin Island, 1871-72, M. W. Harrington, U.S. Coast Survey. 

 W. H. Dall's exploration (MBG S4O20). 



