LICHENS The fungus component of lichens discharges ascospores from typical apothecia or perithecia, or basidiospores from basidia. Fragments of the thallus including both fungal and algal components are blown about freely. Rounded groups of algal cells surrounded by fungal hyphae, separating off from the lichen thallus as soredia, are also blown away; but we know little as yet about the relative importance of these various modes of reproduction.