Practice question

Telome theory proposed by German morphologist Zimmermann explains megaphyll origin through systematic transformation of three-dimensional dichotomous branching systems of Rhyniophyta-like ancestors. Overtopping involves unequal growth of dichotomies creating dominant main axis and subordinate lateral branch systems. Planation brings three-dimensional branches into single plane, and webbing develops photosynthetic mesophyll tissue between planated branches producing broad lamina with branched veins. Enation accounts for microphylls, not megaphylls. Vascular reduction or loss would not generate reticulate lamina complexity observed in fern fronds and seed plant leaves.