# Catadromous venation

**Source**: https://eflora.sydney.edu.au/glossary/catadromous-venation
**Parent**: https://eflora.sydney.edu.au/glossary/

a type of [venation](https://eflora.sydney.edu.au/glossary/venation "the manner in which the veins of leaves are arranged.") in which the first set of veins is given off on the lower side of the [midrib](https://eflora.sydney.edu.au/glossary/midrib "the principal vein which runs from the base to the apex of the leaf.") as in most [species](https://eflora.sydney.edu.au/glossary/species "a taxonomic unit of classification; the largest group of organisms potentially capable of interbreeding to produce fertile offspring for many generations.") of Lastreopsis.

## Related terms

- [Venation](https://eflora.sydney.edu.au/glossary/venation)

- [Catadromous Venation](https://eflora.sydney.edu.au/glossary/image/catadromous_venation "Aspidiacieae: Pinnules of Lastreopsis decomposita with catadromous veins, ridges of the rhachises decurrent along the margin of the pinnules.")