Submerged highly divided leaves in Myriophyllum

No cuticle, stomata, air spaces or sclerenchyma present in submerged leaves

Cross-section of a pinna of a leaf from the submerged hydrophyte, water milfoil (Myriophyllum sp.). The plant has finely pinnately divided leaves which lack cuticle, stomata, sclerenchyma and air spaces in the mesophyll.

Note the centric (unifacial) structure of this pinna. Such form of the leaf may allow for a greater uniform surface for the diffusion of carbon dioxide from the water into the leaf for photosynthesis in the absence of gas channels. The movement of the surrounding water may also better circulate dissolved gasses.