200 Southern Extension of California Flora. [^oe 



southward into the San Ignacio I,agoon and that running north- 

 west into the Pacific. 



It has been shown in Zoe* that the flora of the Cape Region 

 shows a greater aflSnitj^ to that of Sonora than to that of Alta 

 California and a preponderance of Mexican forms prevails as far 

 north as Calmalli, where the vegetation, on account of the 

 disappearance of southern plants and the accession of numerous 

 northern ones, assumes a decidedly Californian aspect. Of course 

 there is not as great a change as would be caused by the inter- 

 vention of a high mountain range or a bod}' of water, but at the 

 lower and middle elevations the traveler from the south soon 

 perceives a difference in the surrounding vegetation after crossing 

 the low divide before reaching Calmalli. 



East and west of this dividing region, higher and as yet 

 unexplored mountains extend southward and doubtless carry 

 along their summits many Californian plants to a lower 

 degree of latitude, and the impossibility of drawing a line 

 between the northern and southern floras is further shown by 

 the fact of maritime species of the Pacific Coast extending 

 their limits southward a greater distance than would be sus- 

 pected, especially upon the islands, in the same manner as the 

 more southern maritime flora is continued northward to those 

 islands oflf the coast of Alta California. 



There is another localit}^ equally important concerning the 

 southern extension of Californian flora and especially interesting 

 in that it must certainly be the most southern habitat of many 

 plants. This interesting region is the high mountain known as 

 San Pedro Martir, situated about one hundred and twenty-five 

 miles southeast from San Diego, and much nearer to the Gulf of 

 California than the Pacific Ocean. It is an extensive plateau 

 rather than a mountain, having an elevation of seven or eight 

 thousand feet and traversed by numerous rock}- ridges reaching 

 two or three thousand feet higher. It is the highest part of the 

 elevated region extending southward from Campo and the Cuya- 

 maca Mountains, which here culminates and falls away at the 

 south to so low an elevation, that in crossing the Peninsula from 



*Zoe iii, 223. 



