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SOME MORPHOLOGICAL FEATURES FOR GENERIC CHARACTERIZATION AMONG THE CASUARINACEAE
Author(s) -
Torrey John G.,
Berg R. Howard
Publication year - 1988
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1988.tb13510.x
Subject(s) - biology , deserts and xeric shrublands , genus , botany , morphology (biology) , evolutionary biology , zoology , ecology , habitat
The family Casuarinaceae has been divided recently into four genera on the basis of differences in chromosome numbers, morphological characters including stem morphology, structures of the male and female flowers and fruits, their modern biogeography, and fossil record. All members of the family are characterized by highly reduced leaves, photosynthetic deciduous branchlets, and adaptations to xeric or hot humid environments. The genus Gymnostoma is characterized by multiple rows of naked stomata along the central vertical faces of the stem internodes. Casuarina and Allocasuarina develop vertically aligned rows of stomata in deep furrows that alternate with stem ridges. Epidermal hairs, formed within the furrows, occur in different species in conformity with other xeric characters. The characters described in this paper conform to the view that the morphological structures represent reduction and specialization rather than primitiveness.