Quadracaea stauroconidia is a species of fungus in the division Ascomycota. This hyphomycetes fungus was formally described as a new species in 2013. The type specimen was collected by the authors from , (Santa Teresinha, Bahia, Brazil), where it was found growing on submerged leaves. The species epithet, stauroconidia, makes reference to the star-shaped conidia (asexual spores).
Quadracaea stauroconidia shares similarities with several related fungal species but can be distinguished by specific characteristics of its reproductive structures. The conidiophores of Q. stauroconidia are unbranched, septate, and erect, ranging in colour from brown at the base to paler towards the apex. These structures measure 84âÂÂ225 üm in length and 3âÂÂ9 üm in width.
The conidiogenous cells, which produce the spores, are terminal or intercalary and cylindrical in shape, measuring 12âÂÂ16.5 üm by 3âÂÂ3.8 üm. These cells are light brown and can sometimes show percurrent proliferation. The separating cells are single or in clusters of up to five, thin-walled, smooth, and pale brown, with dimensions of 3âÂÂ6 üm by 3 üm.
The conidia (asexual spores) are solitary, dry, septate, and constricted at the septa. They are smooth, thin-walled, and stauroform (cross-shaped). The central cell is angular and dark brown, measuring 8.5âÂÂ13 üm by 7.5âÂÂ11 üm. The apical cells are conical and pale brown, with the first cell measuring 4âÂÂ5 üm by 6 üm, and the second cell phialidic, measuring 4âÂÂ5 üm by 3âÂÂ4.5 üm. There are usually two, sometimes one, lateral cells that are conical and rounded at the top, pale brown, measuring 4âÂÂ5 üm by 4âÂÂ6 üm. These lateral cells may sometimes have a middle septum forming a phialidic cell. The basal cell is conical, truncated at the base with a short frill, pale brown, and measures 4âÂÂ5 üm by 5âÂÂ6 üm. The phialidic cells produce smooth, falcate, hyaline conidia that lack septa and measure 7.5âÂÂ9 üm by 0.7âÂÂ0.9 üm.