An embolism is where an air bubble is created in a tracheid.

The other type of tracheary element, besides the tracheid, is the vessel element.

Damage to a tracheid's wall almost inevitably leads to air leaking in and cavitation, hence the importance of many tracheids working in parallel.

That cell, called a tracheid, is the definitive feature that enables land plants to grow upright, unlike mosses and liverworts, which stay close to the ground.

The plant microfossil analysis recovered fragments of conifer tracheid and vessel elements with a ray of parenchyma cells, which corroborates the consumption of wood plants, pollen grains, spores, and fibers.