Leaf lamina. The leaf architecture probably arose multiple times in the plant lineage
Leaf lamina. The leaf architecture probably arose multiple times in the plant lineage, originally uploaded by Jinaa.com.
Leaves are the primary photosynthetic organs of a plant. Based on their structure, they are classified into two types – microphylls, that lack complex venation patterns and megaphylls, that are large and with a complex venation. It has been proposed that these structures arose independently.Megaphylls, according to the Telome hypothesis, have evolved from plants that showed a three dimensional branching architecture, through three transformations – planation, which involved formation of a planar architecture, webbing, or formation of the outgrowths between the planar branches and fusion, where these webbed outgrowths fused to form a proper leaf lamina. Studies have revealed that these three steps happened multiple times in the evolution of today’s leaves
