THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 29 



an appropriate and distinctive meaning, but it need have no special 

 significance and may be totally devoid of meaning or may even be 

 misleading, as when minima is applied to the largest species of a 

 genus. In the present unsettled condition of botanical nomenclature 

 one is often in doubt as to what to do, but it seems* clear that the law 

 of priority should be observed. 



Perhaps no more important work could be done than the careful 

 overhauling of the synonymy of American lichens by someone who 

 has access to the published exsiccata of Europe and America as well 

 as the literature of the subject. 



The author has endeavored to avoid the old conception where the 

 word species was almost a generic term, including a large number of 

 subspecies, varieties, and forms. Nature has no clean-cut, sharply 

 drawn definitions, and perhaps in no organisms are the actual varia- 

 tions and gradations so numerous or more puzzling than in lichens. 

 But, nevertheless, a species should be a pretty distinct and well defined 

 group in which the degree of variability is relatively small. Those 

 forms which present constant differences in the field, or in structure, 

 may be regarded as distinct species, while instead of giving every 

 minor variation a varietal name we should rather work out the eco- 

 logical factors producing them, and not overload an already too bur- 

 densome synonymy. 



While every part of the Santa Cruz Peninsula has been visited 

 many times, certain localities naturally, have been found the richest 

 in numbers or rarity of species. Perhaps first of these stands the 

 region at the head of Devils Canon, a wild region where is found the 

 largest mass of bare rock in the peninsula, and where there is a nearly 

 vertical descent of perhaps 800 feet. Other localities offering peculiar 

 attractions to the collector are the cliffs of the Golden Gate, and of 

 the ocean shore from Point San Pedro to Pigeon Point, and the sand- 

 stone ridges of Castle Rock and vicinity. But as a matter of fact 

 there is not a canon winding down to the ocean, not a group of old 

 forest trees, not an insignificant reef of igneous rock outcropping in 

 the foothill pastures, but will amply repay the intelligent efforts of 

 any collector. 



The Santa Cruz Peninsula is peculiarly rich in endemic species, 

 and although collections in other parts of the state may considerably 

 extend the range of some of them, it is probable that a goodly number 



