The leaf size spectra was dominated by microphyll with 31 (39.74%) species followed by mesophyll (17 sp., 21.79%), nanophyll 14 (17.94%), macrophyll 6 (7.69%), leptophyll 5 (6.41%), megaphyll
2 (2.56%) and one (1.28%) species was aphyllous (Table 2, Fig.
Fleming, "Zimmermann's telome theory of megaphyll
leaf evolution: a molecular and cellular critique," Current Opinion in Plant Biology, vol.
Plants were divided in to, (A) leptophyll, (B) nanophyll (C) microphyll (D) mesophyll and (E) megaphyll
. For this estimation in the area Raunkiaer (1934) diagram was used.
This clade diverged into two lineages: the Prorepens clade, which remained of small stature and tended to become dioecious, and the "Megaphyll
" clade, which tended to increase its leaf size and rank (Figs.
Anomalous branching patterns in some fossil Filicales: Implications in the evolution of the megaphyll
and the lateral branch, habit and growth pattern.
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).
ontogeny, whereas extant cycad megaphylls
are less ephemeral, usually