Date of this Version
Annals of the Missouri Botanical Garden (1986) 73(2): 284-296.
Of Lithocarpus, Castanopsis, Castanea, and Quercus, only Lithocarpus frequently bears branched spikes suggestive of the primitive condition in the Fagaceae; the other genera sometimes have them in some individuals. Simple and branched spikes can occur on the same tree. Evolution of the simple spike is interpreted as the loss of branching capacity in the branched spikes. The Fagaceae show various transitional stages from perfect, entomophilous to imperfect, anemophilous flowers and from mixed-sex to unisexual spikes. Complete separation of staminate from pistillate function into separate spikes and catkins occurs only in Quercus, which is also the only anemophilous member of these four genera. Lithocarpus is the least specialized while Quercus is the most specialized in inflorescence structure of the four genera.