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 (1, 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. 
Il. 
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- 
meles 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 this 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. 
