Definition of crustose in US English:

crustose

adjective

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

    • ‘These two genera are common crustose lichens on coniferous tree trunks.’
    • ‘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.’
    • ‘Geniculate taxa are characterized by larger nuclear genomes and crustose taxa are characterized by smaller with the exception of Neogoniolithon and Titanoderma.’
    • ‘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.’
    • ‘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.’

Origin

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

Pronunciation

crustose

/ˈkrəstōs/