Comprehensive DescriptionRead full entry
General DescriptionColonies. On malt agar spreading broadly, attaining a diam. of 7 to 8 cm within 2 weeks at 25°C, consisting of a basal felt in which numerous ascomata are embedded near the agar surface, usually forming a continuous, thick layer, conspicuous yellow, ranging from Lemon Yellow to Empire Yellow towards the centre often overgrown by a loose aerial network, giving the central areas of some strains, a conspicuous pinkish shade approximating Orange-Vinaceous; very few strains growing less rapidly, about 4.5-5.5 cm diam. within two weeks and producing paler yellow shades, becoming Cream-Buff in age; conidial state scanty, usually not affecting the colony appearance, but in some strains more pronounced, giving the conidial areas a greyish green shade near Gnaphalium Green; after having been maintained for some time on artificial media the species with a strong tendency to produce white to greyish green sectors consisting of a floccose to funiculose mycelium bearing penicilli more or less abundantly; odour present, but unpronounced; exudate lacking, in occasional strains present as small drops; reverse ranging from orange red when young to orange brown in age, with the marginal areas pale ochraceous brown; in a few strains the reverse showing conspicuous purple red shades with the pigment diffusing in the agar; in other strains the red pigment sometimes lacking completely; vegetative hyphae colourless to yellow, often encrusted, 1-4 μm diam. Conidiophores. Arising primarily from the substratum, especially in marginal areas, occasionally borne also as short branches from aerial hyphae overgrowing the ascomata, usually erect, 24-250 × 1.5-2.5 μm; metulae 2 to 3 (-4) in the verticil, 10-15 × 1.7-2 μm, occasionally lacking; in strains producing better developed penicilli, up to 6 metulae occurring in the verticil, measuring 8-12 × 2-2.5 μm. Conidiogenous cells. In whorls of 2 to 7, lanceolate, 8-12 × 1.7-2.5 μm, in fractional penicilli often atypical, solitary conidiogenous cells may be present. Conidia. Brownish green, ranging from subglobose to ellipsoidal, 2.2-3.5 × 2.0-2.5 μm, in other strains slightly smaller or larger, with walls usually thick, smooth or nearly so. Ascomata, Usually yellow, in some strains buff or pinkish to purple-red, globose, 200-700 μm diam., commonly confluent but at the margin occasionally discrete, ripening within 2 weeks; in a few strains ascomata predominantly discrete, forming a thinner layer than produced by the neotype culture; covering consisting of a few layers of well developed networks of yellow pigmented hyphae, not becoming pseudoparenchymatous; surrounded by loose wefts of yellow, heavily encrusted, somewhat twisted, predominantly radiating hyphae, about 1 to 2 μm diam.; initials consisting of club-shaped ascogonia, up to 250 μm in length and 3.5-4.5 μm diam., around which thin antheridia coil tightly several times; the antheridial apical cell usually closely appressed against the ascogonium, fusing with the ascogonium at about the central or somewhat higher portion of the latter cell; after fertilization, the ascogonia becoming septate with at first horizontal and later irregularly transverse and oblique septa developing; at this stage the primordium becoming enveloped in closely wound delicate hyphae, which develop into the covering; most of the ascogonial cells producing branches, which continue to branch profusely. Asci. Usually 8-spored, broadly ellipsoidal to subglobose, 8-11 × 7.5-9 μm, in some strains slightly smaller. Ascospores. Yellow, in strains producing abundant red pigment becoming reddish in age, more or less broadly ellipsoidal, 3.5-5 × 2.5-3.2 μm, in some strains somewhat smaller, thick-walled, spinulose, with spines ranging from very small to 0.5 μm, rarely 1 μm in length.