330 BOTANICAL GAZETTE ' [april 



which cannot be distinguished by its pubescence, may be recognized 

 by the longer lobes of the stigmas and the more or less distinct style. 

 Male specimens of these species sometimes prove difficult to dis- 

 tinguish. In S. sessilifolia leucodendroides the base of the leaves 

 usually is more obtuse and suddenly contracted in the very short 

 petiole, while in S. exigua as well as in 5. Parishiana the leaves are 

 mostly attenuated at the base, passing gradually into the somewhat 

 longer petioles. S. Parishiana normally has linear leaves, while in 

 S. exigua they are more linear-lanceolate, but all those characters 

 have to be taken cum grano salis. There is a specimen before me 

 from southern New Mexico, Dona Ana County, Mesilla, alt. 

 1150 m., June 19, 1897, E. O. Wooton (no. 39, m.; G., St., W.), of 

 which the younger leaves are almost sessile, with a pubescence like 

 those of var. leucodendroides, but are more linear; the older ones, 

 which are more glabrescent and measure up to 12 by o. 5 cm., have a 

 distinct petiole 2-3 mm. long. The pubescence and shape of the 

 bracts seem to vary in the same manner in every species. Whether 

 or not the shape and size of the anthers afford a useful character I 

 cannot state. In those regions where the species meet each other 

 hybrid forms are certain to occur. 



The range of what I call the typical form of S. exigua extends 

 from southern Idaho (from which the type probably came) west- 

 ward to Oregon (where the western line seems to run from about 

 Wasco County to Klamath County) and Washington (where 

 tt hardly reaches the eastern slopes of the Cascades), north- 

 ward to British Columbia (where I did not see it from farther 

 north and west than Clinton on the Fraser River) and southern 

 Alberta (Medicine Hat) , eastward to central Montana and western 

 Wyoming (Yellowstone Park), and southward to southeastern 

 Nevada and southern California. In California it seeins to occur 

 along the eastern border line from Modoc to Inyo County (Pana- 

 mint Range), and in the south (Ventura to San Bernardino, Impe- 

 rial, and San Diego counties). There are also forms very near to 

 it in San Benito, Tulare, and Kern counties, which partly point 

 toward S. sessilifolia var. Hindsiana. From the south I also have 

 seen forms which come very near var. leucodendroides on the one 

 hand and S. Parishiana on the other. As already stated, the 

 limitation of these species is a very difficult task. 



