Abstract
Ascoma initials in the marine ascomycete Corollospora gracilis (Halosphaeriales) are formed from a coiled ascogonium following antheridium-ascogonium conjugation. Dikaryotic ascogenous initial cells derived from the distal end of the ascogonial coil produce ascogenous hyphae that then form the hymenium. Basal regions of the ascogonial coil and the initial investing hyphae form the sterile centrum tissue including the plug, separation layer, and centrum pseudoparenchyma. Pit-connections of the centrum pseudoparenchyma are normal ascomycetous septa. Thick-walled, non-melanized plug cells and a thin melanized separation layer form at the base of the ostiolar canal to delimit the centrum from the external environment. The subiculum that attaches the ascomata to sand grains is comprised of aggregated hyphopodia and mucilage.