Leaf gaps are small areas above the node of some leaves where there is no vascular tissue, as it has all been diverted to the leaf. Megaphylls, in contrast, have multiple veins within the leaf and leaf gaps above them in the stem. Microphylls contain a single vascular trace.

Oct 10, 2019 · Microphylls refers to a type of very shortleaf, such as in moss or clubmoss, with a single unbranched vein and no leaf gaps in the stele while megaphylls refer to a type of leaf with several or many large veins branching apart or running parallel and connected by a …

Jun 2, 2020 · Two basic types of leaves occur in vascular plants, microphylls (Greek mikros + phyllon = small leaf) and megaphylls (Greek megas + phyllon = large leaf). These terms are used to distinguish leaf types that differ in their evolutionary origins and, often, their structural attributes.

Jan 1, 2009 · Microphylls are defined as leaves of small size, with simple venation (one vein) and associated with steles that lack leaf gaps (protosteles). By contrast, megaphylls are defined as leaves of generally larger size, with complex venation and associated with …

Sep 4, 2013 · The leaves of euphyllophytes have been called megaphylls (Gifford and Foster, 1988), and there are several competing theories regarding their evolution. The most widely accepted is the one proposed by Zimmermann (1930).

Megaphylls altered the evolutionary trajectory of terrestrial plant and animal life, the biogeochemical cycling of nutrients, water and carbon dioxide and the exchange of energy between the land surface and the atmosphere.

…photosynthetic tissue produced leaves called megaphylls. There is evidence for the evolution of megaphylls in several plant groups of the late Devonian Period (about 382.7 million to 358.9 million years ago) and early Carboniferous Period (about 358.9 million to 323.2 million years ago).

Microphylls are defined as leaves of small size, with simple venation (one vein) and associated with steles that lack leaf gaps (protosteles). By contrast, megaphylls are defined as leaves of generally larger size, with complex venation and associated with leaf gaps in the stele [3].

Originally coined to emphasize morphological differences, ‘microphyll’ and ‘megaphyll’ became synonymous with the idea that vascular plant leaves are not homologous. Although it is now accepted that leaves evolved independently in several euphyllophyte lineages, ‘megaphyll’ has grown to reflect another type of homology, that of euphyllophyte leaf precursor structures. …

Megaphylls are seen in ferns and more derived vascular plants. In addition to photosynthesis, leaves play another role in the life of the plants. Pine cones, mature fronds of ferns, and flowers are all sporophylls—leaves that were modified structurally to bear sporangia.