84 EBYTHEA. 



coal prepared from the wood of this shrub is in demand for 

 the manufacture of the finest qualities of gunpowder. The in- 

 significant green blossoms of the species are peculiarly- 

 grateful to bees, and goats, sheep and horses devour the 

 foliage, though it is refused by cows. Its rigid spinescent 

 branches adapt it to use in making hedges, for which purpose 

 it was long since introduced into eastern North America, 

 where it is now sparingly naturalized. 



So nearly related to this historic type as to be generally 

 received in the same genus are something like a hundred 

 other species now recognized by botanists. They are dis- 

 tributed all around the northern hemisphere, chiefly within 

 the temperate zone. The species of the southern hemisphere 

 are extremely few. 



In comparison with Europe, to which twenty-three species 

 are credited. North America north of Mexico is not well 

 stocked with Bhamnus; for we can hardly claim more than 

 fifteen, four or five of which are of the Atlantic slope, all the 

 rest belonging to the Pacific slope proper; that is, to the 

 narrow strip of territory intervening between the crest of the 

 Cascades and Sierra Nevada and the shores of the Pacific; 

 neither the Great Basin nor the Rocky Mountain region 

 exhibiting any species, except at the extreme north, where 

 one of the eastern, R. alnifolia, traverses the continent, and 

 becomes the only one common to both the eastern and west- 

 ern floras of the country. 



If, then, eastern North America has of this genus three or 

 four endemic species, the much smaller area of the Pacific 

 slope proper has at least three times as many. Nor could it 

 be expected to be otherwise by any who know and appreciate 

 the vastly greater diversity of soils, altitudes and degrees of 

 humidity existing on that farther side of North America. In 

 California alone the species are distributed upon all altitudes, 

 from the sea-level up to almost seven thousand feet; some of 

 them occurring only where the annual rainfall amounts to no 

 more than four or five inches, others where it amounts to one 

 hundred inches or more. They are distributed all along from 



