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the small number of its species and their uniform distribution; 

 both facts to be accounted for probably by the uniformity of con- 

 dition required by the redwood itself. We collected only about 

 twenty-five species in this region, and could have found neady 

 the whole number along any given mile of trail. 



On occasional plateaus and gently rounded summits in the 

 higher portions of the belt, and becoming more numerous further 

 on, where the redwood gives place to oak and spruce, are small 

 patches destitute of trees, commonly known as prairies. In these, 

 of course, the flora is of an entirely different character from that 

 of the forests, and is also much more varied, so that in the west- 

 ern part of the county the greater number of species are to be 

 found in these small prairies. 



Getting farther away from the coast, the country becomes 

 continually more broken, and the flora more diversified. Very 

 few species are found continuously over any considerable area, 

 and rapid changes within short distances are continually met 

 with. When the county comes to be thoroughly explored, it w 

 be found to have a greater number of practically distinct floras 

 than many of the larger states. The passage over South Fork 

 Mountain, in the eastern part of the county, ofifers perhaps as 

 sudden and peculiar a change of flora as can be found anywhere. 

 The mountain is a ridge extending in a nearly north and south 

 direction for several miles, and reaching an altitude of perhaps six 

 thousand feet, the two sides being of nearly equal slope. The 

 western side is bare of trees, except for an occasional clump ^f 

 oaks, but well covered with brush, which consists chiefly of Ceano- 

 thus cuneatiLs, replaced just at the summit by almost impassa 

 thickets of C. divaricaiiis. This mountain side proved to be one 

 of our richest collecting grounds, many species growing in abun- 

 dance which were found rarely or not at all elsewhere. O^ the 

 level space of sandy soil at the summit occurred some species 

 peculiar to such situations, as the magnificent Lilizmi Washing- 

 tonianum of Kellogg, Calyptridinm nttdiim, Greene, and a large 



ill 



ble 



Men 



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ginning the descent we found a few specimens of Pentslcnion 

 Rattani, Gray, and then came the change. We passed suddenly 

 into the shade of a dense forest of coniferous trees, principally 



