large leaves of higher plants that derive from modified (usually flattened) branches that have taken on a leaflike shape. In macrophylls, leaf gaps usually form in the leaf traces (in contrast to microphylls in which leaf gaps do not form). Macrophyllous and microphyllous plants originate from the Psilophytoidea, in which the body consisted of axial dichotomously branching sections, or telomes. In the subsequent course of evolution, some plants—the microphyllous ones—developed outgrowths on the axes in the form of spines or appendages into which the branches of the axis cylinder entered without leaf gaps; in other plants—the macrophyllous ones—small branch-lets (systems of telomes) became extremely crowded, flattened, and coalesced, assuming a leaflike shape, with the formation of leaf gaps in the central cylinder. Macrophylls are characteristic of many Pteridophyta, Cycadopsida, and all angiosperms.
REFERENCESMeier, K. I. Morfogeniia vysshikh rastenii. Moscow, 1958.
Eames, A. J. Morfologiia tsvetkovykh rastenii. Moscow, 1964. (Translated from English.)
L. V. KUDRIASHOV