The Central American Species of Quercus 



INTRODUCTION 



The first complete review of the Central American oaks appeared 

 in A. de Candolle's treatment of the entire genus, as then known, in 

 1864 (I). 1 This very full descriptive compilation lacks both keys and 

 illustrations. In 1869 Oersted treated these species, together with 

 the more northerly ones, in a sumptuously illustrated tome based 

 upon the work of the then deceased Liebmann (2). No more recent 

 work on the subject can compare with the beauty and usefulness of 

 this luxurious volume, and it is not likely that so ambitious a publica- 

 tion will soon again be issued. Much less significant is a treatment 

 of the American species in 1884 by Wenzig (7). The last complete 

 treatment of the species of Central America appeared in Trelease's 

 monumental treatise (6) on the American oaks in 1924. 2 This work 

 includes illustrations of the types of most of the species as well as of 

 representative variations of nearly all species. 



It has been found necessary to reduce many of the species erected 

 by Trelease in his monograph and by various authors subsequently. 

 Most of the species that have been placed in synonymy seem to have 

 been described from too little material to serve as a basis for specific 

 distinction. Subsequent collections, and even mere comparison of 

 the types with an abundance of earlier collections, have clearly indi- 

 cated the necessity of numerous reductions. The lack of any suitable 

 disposition of these indistinct species has motivated the present 

 treatment. 



It must be emphasized, however, that these reductions to synonymy 

 do not constitute an unfavorable commentary upon the usefulness of 

 Trelease's monograph. The mere fact that his species concept ad- 

 mitted entities too fine to avoid confusing the casual user of his work 

 in no way reflects upon his accuracy in analyzing the phylogenetic 

 situation. In many instances the erection of several too closely 

 related species, each adequately illustrated, has presented a clear 

 picture of the intraspecific variation of the whole. 



Recent explorations incidental to the floristic studies of Standley 

 and Steyermark in Guatemala and of Woodson and Seibert in Panama 

 have added tremendously to the data that need incorporation into 

 the knowledge of Central American oaks. It was the task of preparing 

 treatments of the Guatemala and Panama species to be included in 

 these floras that most emphatically indicated the need of a review of 



1 Italic numbers in parentheses refer to Literature Cited, p. 90. 



2 The date of this work was erroneously given in the Gray Herbarium card index as 1925. Consultation 

 of the records of the National Academy of Sciences revealed that the Academy received the publication from 

 the printer on November 5, 1924, and immediately placed several copies in the mail. Prior to January 1, 

 1925, 210 copies had been distributed. The date of publication is therefore correctly given on the title page 

 as 1924. 



