Colonies effuse, punctate with shining black sporodochia. Mycelium immersed or partly immersed, com¬posed of branched, septate, subhyaline to pale brown hyphae 2.5-11 µm wide. Sporodochia scattered or crowded, elliptical to rounded, pustulate or flattened, as small as 100 µm or up to 1 mm long, composed of a base of densely aggregated hyphae bearing crowded conidiophores which are centrally erect and marginally diverging. Conidiophores simple, straight or slightly curved, with a thin outer gelatinous layer, composed of a sessile or stalked conidiogenous cell; when present the stalks are up to 20 µm long, subhyaline to pale brown, cylindrical and 4.5-5.4 µm wide. Conidiogenous cells brown, 6-14.5 µm long, 4-5.4 µm wide below, expanding to 5.6-8 µm at the distal end which may be flattened or slightly convex after conidium secession. Percurrent proliferations are narrowed as they extend through the half-septum retained by the conidiogenous cell after conidium secession and then expand into a shortly-stalked conidiogenous cell: one to three such percurrent pro-liferations have been seen on conidiophores.

Conidia are solitary, blastic and terminal on the conidiogenous cells and their successive proliferations. They are obovoid, brown, slightly paler at the ends, mostly 5-septate with the two central cells much larger than the paired end cells: conidia are flattened at the basal scar, which is 6.3-8 µm wide, and they are at first rounded at the apex. They measure 50-65 x 23.5-30.5 µm. Occasional conidia are 4-septate with an inordinately large, single central cell with two small cells at each end, or they may be 6-septate with an extra, small cell at base or apex. Occasionally, three central cells maybe larger than the others. Seven-septate conidia are rare. Whilst still attached to their individual conidiogenous cells conidia usually produce up to 9 small and more or less globose conidia of a synanamorph from the distal cell of the conidium: these are sessile or borne on a short, simple or branched stalk. They are pale brown to brown, 9-12.5 µm wide with a configuration of cells reminiscent of textura epidermoidea. The thin gelatinous layer which surrounds the conidiophore also extends over the conidia and their apical synanamorph.

On rotten wood, Auckland Province, (1) Nothofagus menziesii, Mangorewa Gorge, 20. III. 1963, S.J. H., DAOM 167421; (2) unidentified host, Centennial Track, Upper Piha valley, Waitakere Range, 2.V.1963, S.J.H., PDD 20961 (type) (DAOM 93817).

Coloniae effusae cum sporodochiis atris punctatae. Mycelium immersum vel partim superficiale, ex hyphis ramosis, septatis, subhyalinis vel pallide brunneis 2.5-11 µm crassis compositum.Sporodochia dispersa vel aggregata, elliptica vel rotundata, pustulata vel depressa, ca 100 µm diam. vel ad 1 mm longa.Conidiophora simplicia, brevia, recta vel parum curvata, dense aggregata, ex cellulis conidiogenis smgulis breviter stipitatis vel ex cellulis conidiogenis sessilibus composita. Stipes ad 20 x 4.5-5.4 µm, subhyalinus vel pallide brunneus cylindricus. Cellula conidiogena brunnea 6-14.5 µm longa, basi 4-5.4 µm crassa, ad apicem 5.6-8 µm crassa. Dein conidiophora (cellulae conidio¬genae) proliferunt per proliferationes conidiogenas ad 3 percurrentes.

Conidia solitaria, blastica, primo in apice cellulae conidiogenae et dein proliferationis cujusque successive oriunda, obovoidea, brunnea, ambitu pallidiora, plerumque 5-septata, cellulis binis centralibus majoribus alias biros apicalibus basalibusque parvioribus, 50-65 µm longa, 23.5-30.5 µm crassa. Conidia et conidiophora circumdata sunt tumca gelatinosa tenue.Conidia secondaria 1-9 sessilia vel breviter stipitata super cellulam apicalem oriunda, subglobosa, pallide brunnea vel brunnea 9-12.5 µm diam. Paries aliter dictu "textura epidermoidea".

Holotypus in ligno putrido, Nova Zelandia, "Auckland Province, Centennial Track, Upper Piha Valley, Wai¬takere Range", 2.V.1963, S. J. Hughes, PDD 20961 (DAOM 93817).

The conidia of Hadrosporium dingleyae are smaller than those of the type species, have fewer septa, and they bear a synanamorph at the distal end. Hughes (1979) indicated that the conidia of the synanamorph produced by the new species are similar to those produced by species of Xenosporium Penzig et Saccardo (Hughes 1978). The production of nested proliferations by species of Hadrosporium is paralleled in Phragmospathula Subramanian et Nair (Hughes 1979) but there are apparent differences in the origin of these proliferations. A better understanding of these genera would certainly result from a closer investigation, especially at the ultrastructural level. Many proliferations in Hadrosporium dingleyae seem to have arisen within the conidiogenous cell itself. In others the proliferations appear to have arisen by an extension of the lower septum of the conidiogenous cell or from an extension of penultimate cell through that septum.