(Of a plant) growing on the surface of rock:most seaweeds are epilithic...
We have virtually no fossils of tropical fleshy algae, especially the small soft epilithic species that characterize primary productivity on modern reefs.
This community is also characterized by a high epiphytic and epilithic cover.
We investigated the importance of snowmelt as an organizing factor for epilithic microalgae in a high-altitude montane stream during 3 yr of differing melt characteristics.
Origin
Early 20th century: from epi- 'upon' + Greek lithos 'stone' + -ic.