 The hamathecium (hyphae or other tissues between asci) is composed of persistent cellular pseudoparaphyses (hyphae originating above the level of the asci and growing downwards between the developing asci), in a gel matrix, with tips often darkened or branched at maturity to form an epithecium (the external layer of tissue of the fruiting body of lichens and fungi, formed by the union of the tips of the paraphyses over the spore sacs).Bitunicate (double-walled) asci are borne in a basal layer and at maturity are typically club-shaped to cylindrical, bearing eight ascospores, overlapping in two series, ranging from hyaline to dark brown, obovoid, clavate, ellipsoid or fusoid.Ascospores are highly diverse in septation, and range from didymospores to phragmospores to dityospores, at times surrounded by a gel coating, and often show bipolar asymmetry.