356 



BOTANICAL GAZET7 E 



[MAY 



QUERCUS VELUTINA. The last of this series, Q. velutina, has a very 

 closely campanulate, thin and delicate perianth. The diameter is the 

 same as in Q. coccinea, 3.5-4 mm . The midrib is entirely 

 wanting. The perianth is pilose, and the cilia along the 

 margin are long and matted. The throat of the peri- 

 anth is so narrow that it is torn by the stamens, as soon 

 as they begin to develop, into two or three nearly equal 

 segments. In the majority of cases the perianth had sepa- 

 rated into two equal segments., but occasionally one was 

 found with three, never with more. 



The results of this study show that there is marked 

 variation among the flowers, not only in the case of the 

 large groups, but also among the species in each, and the 

 following key was based on these characters : 



FIG. S.Q. 

 velutina. 



KEY TO NATIVE OAKS BASED ON THE STAMINATE FLOWERS. 



A. Stamens six to nine. 



I. Bract persistent after anthesis . . ' - . . Q. acuminata 

 II. Bract deciduous before anthesis. 



a. Perianth deeply lobed. 



1. Lobes narrowly linear . . .' . Q. macrocarpa 



2. Lobes obovate or spatulate . . ... Q. prinus 



b. Perianth with shallow lobes. 



1 . Perianth slightly campanulate : diameter 2-3 mm . Q. alba 



2. Perianth rotate : diameter i-2 mm . . Q. platanoides 



B. Stamens four or five. 



I. Midrib wanting . . .....* . . Q. velutina 



II. Midrib present. 



a. Perianth pilose _ .; . , . . . . Q. coccinea 



b. Perianth smooth with lobes thinly ciliate . . Q. rubra 



W. W. ROWLEE and SUSIE P. NICHOLS, Cornell University. 



