19 - Ascoidea Brefeld & Lindau

Abstract

This chapter focuses on Ascoidea genus and its constituent species. The colonies of this species are smooth, moist or dry, mostly with an expanding, submerged mycelium. Its species are often dimorphic, with colonies being restricted and yeastlike or expanding and hyphal. Wide, true hyphae are present and form blastoconidia, which are sessile or on denticles and occur singly or in short branched chains. Asci are lateral or terminal on hyphae, ellipsoidal or acicular, with firm walls, and contain numerous ascospores, which are liberated through a terminal opening. New asci are formed percurrently inside the remains of a previous ascus and the ascospores are ellipsoidal, with a unilateral, mucilaginous brim. Fermentation and urease are absent, and diazonium blue B reaction is negative and rarely weak. The constituent species of this genus are Ascoidea africana, Ascoidea corymbosa, Ascoidea hylecoeti, and Ascoidea rubescens. In Ascoidea africana, asci are formed singly or in small whorls alongside hyphae, mostly inserted just below distal septa. They are broadly ellipsoidal with firm walls containing 16-70 ascospores, which are liberated by apical deterioration of the ascus. The asci of Ascoidea corymbosa are formed in small groups in distal portions of hyphae. They are mostly ellipsoidal with firm walls and contain 16—40 ascospores, which are liberated by apical deterioration of the ascus. The asci of Ascoidea hylecoeti are borne terminally on erect hyphae, later becoming lateral due to further growth of supporting hypha. Its ascospores are ellipsoidal, which appear hat-shaped due to a unilateral mucilaginous fringe.