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without the purplish tint. Yet in certain genera, for reasons 

 which are obscure, there appears to arise a condition of mutabil- 

 ity on islands, and perhaps we may say in general, at the 

 periphery of the range. Such mutability is evidently advan- 

 tageous, in that it provides the material for extensions into new 

 territory, some of the variations being advantageous in the 

 new environment. If the insular variability is an expression of 

 such a tendency, we may suppose that it occurs principally 

 during a period following the introduction of the species, and 

 that after a time one of the forms proves best fitted to survive, 

 and prevails to the exclusion of the rest. Thus such a species as 

 Astragalus miguelensis would be a climax type, now stable; 

 while certain of the poppies, Dendromecon and Eschscholtzia, 

 are still in the variable stage, so that the number of "valid" 

 forms is uncertain. It is evident that the thoughtful biologist, 

 anxious to understand the processes of nature, will wish to 

 study all these variable plants, and will not contemptuously 

 dismiss them as "bad species." 



Phacelia scahrella is one of the plants described by Greene 

 from San Miguel, but it is ignored by Munz, who regards it as 

 identical with P. distans Bentham. I found it dried up at the 

 time of my visit but on one plant were two of the beautiful 

 light blue flowers, and bees of the genus Anthidium were flying 

 over it. Brand recognized P. scahrella as a variety of P. distans, 

 occurring in the Coast Range northward, but southward only 

 on the islands. It would thus fall in with a long list of plants 

 cited by Munz as having a similar distribution. 



The islands have suffered from the influence of man es- 

 pecially in two ways; they have been greatly overgrazed, and 

 very numerous weeds and other plants have been introduced. 

 The introduction of various forms of animal life is likely to also 

 prove injurious. Thus, as Mr. E. Z. Rett explains to me, the 

 foxes on Santa Cruz, about 1927, got scab from the sheep, and 

 were almost exterminated, though they are now increasing 

 again. This trouble has not occurred on San Miguel. Mr. D. B. 

 Rogers informs me that Santa Barbara Island is now full of 

 rabbits (introduced), and these must seriously aff'ect the native 

 flora. In a good many cases, the accidentally introduced plants 

 are represented by only a few specimens, and do not appear to 

 spread. Thus on San Miguel, 51 years ago, Greene said of 

 Marrubium vulgar e, "a single plant but that in flower and 



