Page 9 - Lesson Notes-Morphologyof flowering plant

veins which in turn branch to form veinlets.
The lamina is the seat of photosynthesis, gaseous exchange, transpiration and other
metabolic activities. The shape, margin, apex, surface and extent of invision of
lamina varies in different leaves.

Venation
The arrangement of veins and veinlets in the lamina of leaf is called venation. The
midrib, veins and veinlets are contain vascular tissues, i.e., The xylem and phloem for
conduction water, mineral salts and food.
Leaves have mainly two types of venation
i. Reticulate Venation
When the veinlets form a network, the venation is called reticulate. It is found in dicot
leaves. However, some monocot leaves like Smilax, Dioscorea and Alocasia also
show reticulate venation.
ii. Parallel Venation
When the veins run parallel to each other within a lamina, the venation is termed as
parallel, e.g. Calophyllum, Zingiber officinale, etc.