i goo] BRIEFER ARTICLES 353 



THE TAXONOMIC VALUE OF THE STAMINATE FLOWERS 

 OF SOME OF THE OAKS. 



(WITH EIGHT FIGURES) 



THE flowers of the oaks have received comparatively little attention 

 from investigators in systematic botany. Most authors have described 

 the flowers of a single species, usually Quercus alba, which they have 

 considered as a type for the entire genus. Sargent in his Silva has 

 given a brie! description of the flowers of each species, but the degree 

 of variation in the form of the lobes and the amount of pubescence is 

 hardly touched upon. 



The present study was undertaken in order to determine whether 

 there was not a wider range of forms among the flowers, and, if so, 

 whether this variation is constant enough to aid in the separation and 

 limitation of the species. For this purpose the staminate flowers of the 

 oaks in the Cayuga Flora (Q. acuminata, Q. alba, Q. platanoides, Q. Prinus, 

 Q. macrocarpa, Q. rubra, Q. cocdnea, and Q. velutind] were chosen. 



Staminate flowers were collected from as many trees of each species 

 as possible at anthesis. The flowers were opened, the stamens 

 removed, and the perianth mounted in glycerine jelly. In order to 

 determine the limits of the midrib it was found of assistance to warm 

 the slide after mounting. 



The oaks may be divided into two groups, one containing those 

 which require a single season for maturing their fruit, the other 

 requiring two seasons. Of the oaks enumerated above the first five 

 belong to the first group, the last three to the second. This same 

 division is substantiated by a study of the floral organs. 



The first group has a six-lobed perianth that is campanulate to 

 rotate, and has six to nine stamens. The second group is easily dis- 

 tinguished from the first by its closely companulate perianth, and the 

 stamens are four or five in number. The different species in each 

 group may be distinguished by the size and shape of the lobes, the 

 amount of pubescence, and the presence or absence of a midrib. 



QUERCUS ACUMINATA. This species has a six-lobed, thin, and deli- 

 cate rotate perianth, which is 3 mm in diameter. The lobes are usually 



