The Comparative Morphology of the Fagaceae I. The Genus Nothofagus

Abstract

The present studies of Nothofagus constitute a section of a comparative survey of the sporophytic characters of existing genera of the Fagaceae which has as its primary objectives a clearer definition of the generic characters of the entire beech-oak-chestnut assemblage as well as the acquisition of further information bearing on the ancestry of the amentiferous angiosperms. Data from the survey of the morphology of species of Nothofagus have revealed: (a) distinctive histological and anatomical features of the foliar organs, especially of the evergreen spp.; (b) details of variation in inflorescence and floral structure in species of the genus, in particular that of the pistillate flower-heads; (c) internal morph. characters in flowers and fruits sufficiently constant in nature to be of diagnositic value in a definition of this genus. The more typical members of the genus, i.e., those native to antarctic S. America and to the Australian-New Zealand area, in their predominately small evergreen leaves and tricarpellate florets[long dash]the pistillate flowers and the fruits associated usually in groups of 3 within a woody and conspicuously glandular 4-valved cupule[long dash]exhibit a combination of characters which are probably the most primitive to be found in existing members of the beech series, if not in the entire Fagacean assemblage. The beeches from the Netherlands New Guinea[long dash]concerning which there has been some question as to position in the Fagaceae[long dash]display characters, vegetative and floral, which are distinctly those of Nothofagus; although in certain respects sufficiently unlike the more typical members of this genus to justify their reference to a new section of the evergreen beeches.