goniocyst (noun, pl. goniocysts; variant spelling: goniocystula, pl. goniocystulae) – a small (ca. 12-40 um diam.) aggregation of photobiont cells surrounded by short-celled hyphae without an amorphous layer, forming a discrete, ecorticate, ± globular structure which is not a soredium because the photobiont is completely enclosed; e. g., (1) granular thallus particles forming the Botrydina stage of Omphalina sp. (i. e., the anamorphic, thalline part of a basidiomycetous lichen); (2) granular, asexual reproductive particles produced within goniocystangia of some tropical foliicolous lichens; (3) granular thallus particles produced by Micarea spp.