Definition of crustose in English:



  • (of a lichen or alga) forming or resembling a crust.

    • ‘These two genera are common crustose lichens on coniferous tree trunks.’
    • ‘In foliose lichens, there is a second cortex below the medulla, but in crustose and squamulose lichens, the medulla is in direct contact with the underlying substrate, to which the lichen is attached.’
    • ‘Coarsest openings are considered to be exopores of short, subcylindrical exhalant canals that extend from the dermal surface inward to about mid-thickness of the crustose sponge.’
    • ‘Geniculate taxa are characterized by larger nuclear genomes and crustose taxa are characterized by smaller with the exception of Neogoniolithon and Titanoderma.’
    • ‘This tome includes detailed entries on more than 800 foliose, fruticose, and crustose lichens; essays on the biology, structure, uses, and ecological significance of these plants; and hundreds of color photographs.’


Late 19th century: from Latin crustosus, from crusta (see crust).