[f. LICHEN sb. + -ISM.] The special symbiosis between alga and fungus occurring in lichens.
1887. Garnsey & Balfour, trans. De Bary’s Fungi, 419. Species of Algae … so adapted to lichenism that they can no longer attain their full development outside the Lichen-combination.
1895. Oliver, trans. Kerner’s Nat. Hist. Plants, II. 692.
