36 Botany of Mariposa. [zoe 



Hordeum viurimim L. P. C. 

 Elymus condensatus Presl. C. 



Sibiricus L. C. S. 



Sitanion Schult. P. C. 

 Polypodium vulgare L. C. S. 

 Gymnogramme triangularis Kaulf. C. S. 

 Pellcta andromedaefolia Fee. C. 



Ornithopus Hook. C. 

 Pteris aquilina L. C. 

 Woodwardia radicans Sni. C. 

 Aspidium rigidum Sm. C. S. 



munitum Kaulf. C. 

 Cystopteris fragilis Bernhardi. C. S. 

 Selaginella rupestris Spreng. C. S. 

 AzoUa Caroliniana Willd. P. 



This list shows that out of 318 native species common to this dis- 

 trict and the coast, as above defined, only 105, or about one-third, 

 are found in the intervening plain. It is possible, but not probable, 

 that a more thorough exploration of the plains would add something 

 to the number of the species found there, but could hardly produce 

 any serious change in the ratio. On the other hand, out of the 66 

 naturalized plants enumerated, 59 are pretty certainly found on the 

 plains, showing that the)- have accompanied the successive waves of 

 immigration which first swept over the foothills in the search for 

 gold, but have now largely flowed back upon the plains, seeking 

 the agricultural treasures of the soil. 



A further examination of the same list shows how rapidly the 

 plants of the plains and lower foothills disappear as we ascend into 

 mountains. Of the 105 plants of the plains found in this zone, only 



37 reach the coniferous belt and only three the subalpine district. 

 Probably there are really only two of these, as Achillea rnillefolhwi 

 is pretty certainly naturalized on the plains, having been introduced 

 with grass seed. Out of the 213 remaining species 115 extend into 

 the coniferous belt, of which 27 reach the subalpine region. Two 

 of these, Dodecatheon Meadia and Eriophyllimi cczspitosuiii, attain 

 the alpine summits in some of their varieties which, however, may 

 yet be specifically distinguished from the lower forms. 



Coming now to the species really characteristic of or limited to 



