The Comparative Morphology of the Fagaceae I. The Genus Nothofagus

Anatomical features, not hitherto reported, found to characterize the foliar organs, expecially of the evergreen species of the genus Nothofagus, include: (a) heavy cuticularization; (b) lignification of the cells of both the epidermal and the hypodermal tissues, the latter occasionally several layers in extent; (c) grouping of hypodermal cells into ribs in association with the vascular tissues; and (d) occurrence in the larger-leaved species of scalariform-perforated transfusion elements bordering, or in the immediate vicinity of, the sclerenchyma-sheathed veins. 2. Internal morphological characters in the flowers and fruits, which have been determined to be sufficiently constant in nature to supplement external morphological characters in a definition of this genus, include: (a) the occurrence of generally heavy, though variable, amounts of sclerotinization both of the ovary wall and of the cupular valves; (b) a distinctive type of origin and vascularization of the placentae; (c) the occurrence of distinctive multicellular resin-secreting glands in association with either the dorsal or the ventral surfaces of the involucral scales, the cupules of certain of the species-in their peculiarities of glandular structure-bearing a striking resemblance to the gland-bearing husks enveloping the seeds of the Lyginopterideae. 3. The anatomy and morphology of the flowers and inflorescences of species of this genus furnish evidence in support of (a) the origin of the basic triflorous inflorescence characterizing the Fageae from an ancestral many-flowered dichasium, the individual florets of this hypothetical cyme being trimerous and probably bisporangiate, and of (b) the evolution of the lobular type of cupule in association with the pistillate florets as the product of reduction and general modification, including fusion, of sections of this originally more complex cymose inflorescence, such modification accomplishing greater protection for a few of the more advantageously located florets and fruits. 4. The beeches from Netherlands New Guinea, concerning which there has been some question as to position in the Fagacean series, have been found to exhibit a combination of morphological characters in their foliage and reproductive structures which is distinctly that of Nothofagus, although in certain respects they are sufficiently unlike the more typical members of that genus to justify their reference to a new section of the evergreen beeches.