VOL. III.] Botany of Mariposa. 25 



other islands, especially those nearer the coast northward, except 

 Cedros Island, which furnishes but one, while Coronados Islands 

 have two, and the Santa Barbara group two to seven each, of which 

 nearly all are absent from the main land. Guadelupe, 100 miles off 

 shore, and volcanic, has been stocked by chance importations from 

 the latter group (No. 21), the peninsula (i, 23, 20?), and the last 

 three are the only species said to be common to the peninsula and 

 the main land of Mexico. The relation of these facts to the dis- 

 tribution of the species, may be perhaps explained by the small 

 shells most easily adhering to birds roosting on the ground. 



MARIPOSA COUNTY AS A BOTANICAL DISTRICT. 



II. 

 BY J. w. congdon; 



In mentioning in the former article the shrubs forming the bulk of 



^the chaparral of the wooded foothills, the Christmas Berry ( Hetero- 



nieles arbutifolia) was accidentally omitted. Its abundant and 



beautiful bunches of red berries are very noticeable, in the winter, 



on nearly all our hillsides. 



In discussing the herbaceous vegetation of Ihis zone, it has seemed 

 to me, that instead of giving a mere enumeration of peculiar or in- 

 teresting plants, there would be some real scientific value in a 

 somewhat detailed comparison of its flora with the flora of the cor- 

 responding portion of the Coast region. I include under the latter 

 designation the territory between the Coast line and the western 

 edge of the San Joaquin plain, with the Bay of Monterey for its 

 southern and Mendocino County for its northern boundary. 



Perhaps the most interesting and significant result of such a com- 

 parison is the great number of common species found in these 

 tracts separated from each other by the wide expanse of the San 

 Joaquin plain, here of an average width of at least forty-five miles. 

 This intervening plain has a vegetation of its own, consisting of the 

 most common Californian types, mingled with a few peculiar forms 

 limited to that region, and it therefore constitutes with its western 

 boundary of the interior Coast Range a real interruption of the 

 continuous distribution of the great majority of these common 

 species. 



