Venation: The arrangement of veins and veinlets in leaves (Lamina) is known as venation.  It is of 2 types:- 

• Reticulate : It is found in dicots. Exception – Calophyllum, Eryngium. It has parallel venation.
• Parallel : It is found in monocots. Exception – Smilax, Dioscorea, Alocasia, Colocasia. It has reticulate venation.

Reticulate Venation 

In Reticulate Venation main vein divided into various branches (veinlets) and form a net like structure. Reticulate venation is of 2-types.

• Unicostate or pinnate: In this type of venation leaf have only one principal vein or midrib that give off many lateral veins which proceed toward margin and apex of lamina of the leaf and form a network. eg. Mango, guava, Peepal,
• Multicostate or palmate: In this type of venation many principal veins arising from the tip of petiole and proceed towards tip of lamina. This is again two types –
  • Multicostate divergent: Many principal veins arising from the tip of petiole, diverge from the another toward the margin of leaf blade eg. Cotton, Caster, Cucurbita, grape.
  • Multicostate convergent: Many principal veins arising from the tip of petiole. At the base of leaf they are closely arranged but diverage from one another in middle part and converge towards the apex of leaf. eg. Camphor, Zizyphus, Tejpat, Chinarose, plum.

Parallel Venation

In this type of venation, all veins run parallel to each other and they do not from network. They are of 2 types.

• Unicostate or pinnate: This type of pattern having only one principal vein, that gives off many lateral veins, which proceed toward the margin of leaf blade in a parallel manner but they donot have veinlets. eg. Banana, Ginger, Canna.
• Multicostate or palmate: Having many principal veins arising from the tip of the petiole and proceeding upwards.
  • Multicostate divergent: Many principal veins arising from the tip of petiole and diverge toward themargin of leaf. They donot divide into veinlets and do not form network. eg. Coconut, Date palm
  • Multicostate convergent: Many principal veins arising from the tip of petiole run in a curved manner in lamina and converge towards the apex of leaf blades. eg. – Wheat, Sugar-cane, Bamboo.
  • Furcate venation: The veins branch dichotomously but the reticulum is not formed by the finer branches. eg. Adiantum (fern).

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By Team Learning Mantras