PREFATORY NOTE. 



The present volume embodies the results of a prolonged and 

 studious examination into the flora of western middle California. It 

 is, in brief, an attempt to present in book form an account of the 

 seed plants of the region by descriptions of the living plants — of the 

 plants as they actually exist. It is as little as may be at the present 

 time a revision of what has been written about plants of the region, 

 or of plants or of species ascribed to it. The author has enlarged his 

 laboratory and herbarium experience by innumerable excursions and 

 expeditions into the canons and mountains, through the valleys and 

 along the water-curses of California. The diagnoses have been 

 derived mainly from fresh specimens collected by the author or by 

 his colleagues in the Department of Botany, and from similar abun- 

 dant material supplied by many helpful correspondents resident in 

 various parts of the state. 



As to the recognition of species, that is the determination of the 

 number of species present in our region and the working out of their 

 relationships, field studies played an important part. In the larger 

 or more variable genera resort was had to the following method: The 

 material of a given genus was segregated into a certain number of 

 forms (regarded as distinct) or varieties of these forms, the judgment 

 passed being in large measure controlled by field studies. The 

 descriptions of such forms were drawn up from fresh material or 

 herbarium material. The results of these studies could not in all 

 cases, h«»wover, be correlated with the existing literature, but to the 

 descriptions such names were applied as were available in the litera- 

 ture and with all care and caution. Therefore, a particular descrip- 

 tion stands for a natural type (that is to say the usual or dominating 

 or most marked form), while the name may belong to a form of the 

 species which is unusual or abnormal, or may, indeed, belong to a 

 very different plant since the original description by which such a 

 name was published may be so vagu», so loose, or so broad that exact 

 determination is difficult or impossible. Difficulties of this nature 

 may only be settled by a study of the original or type specimens, but 

 these are, to us, largely inaccessible. Moreover, type specimens are 

 not infrequently so poor or so fragmentary that nothing can be made 

 of them. It should be understood, therefore, that the author's con- 

 epption of the species here given place is expressed by the descriptions 

 rather than by the names; that there is here an account of the plants 

 of the region rather than a list of species gleaned from the literature. 



One other course was open. Instead of presenting a fresh account 

 of the plants known to us as occurring in our region it would have 

 been quite possible to list the species attributed to middle California 

 and copy the paraphrased descriptions which we have inherited, 

 adding more or less new matter and emending where it seemed neces- 

 sary. To one, however, whose facilities as to type-specimens are 

 limited but whose advantages as to the study of the living flora are in 



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