What is "soredium"

Soredium \So*re"di*um\, n.; pl. Soredia. [NL., fr. Gr. ? a heap.] (Bot.) A patch of granular bodies on the surface of the thallus of lichens.

n. (context lichenology English) A scalelike structure of algal cells in a lichen, enveloped in a network of hyphae and capable of independent vegetative growth.

Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or green algae. Fungal hyphae make up the basic body structure of lichen. The soredia are released through openings in the upper cortex of the lichen structure. After their release, the soredia disperse to establish the lichen in a new location.