Macrophylls

Macrophylls

 

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.

REFERENCES

Meier, K. I. Morfogeniia vysshikh rastenii. Moscow, 1958.
Eames, A. J. Morfologiia tsvetkovykh rastenii. Moscow, 1964. (Translated from English.)

L. V. KUDRIASHOV

References in periodicals archive ?
The LMEB has more macrophylls, and more compound and entire leaved species than the other two forests.
% Leaf size ** Macrophyll 14 10.14 0 0 Mesophyll 81 58.70 30 56.60 Microphyll 41 29.71 23 43.40 Nanophyll 2 1.45 0 0 Leaf type Compound.
Using Raunkiaer's scale for the classification of leaf size, leptophylls are leaves have a surface area less than 0.04 sq in (25 sq mm) (the term is also used for the plants that bear them); nanophylls are leaves between 0.04 and 0.4 sq in (26 and 225 sq mm); microphylls are leaves between 0.4 and 28 sq in (226 and 18,225 sq mm); macrophylls are from 28 and 254 sq in (18,226 and 164,025 sq mm); and megaphylls are leaves that have a surface area greater than 254 sq in (164,026 sq mm).