Table 3.

Differentiating features of the nonglobose sporangium-producing Mucorales

Organism nameColony morphologySporangium morphologyApophysis and columella morphologySporangiospore morphology
Absidia corymbifera Floccose; first white, turning brown to greenish brown with agePyriform, 20–80 μm in diameterApophysis: flask shaped Columella: dome shaped, occupying about 50% of the sporangiumRound to oval, 2–3 by 3–5 μm
Apophysomyces elegans Floccose, rapidly growing colonies; pale gray to yellowish, turning brown at 37°CPyriform, 20–58 μm in diameterApophysis: prominent bell or “champagne glass” shaped Columella: dome shaped, 18–28 μmOval and light brown, 5.4–8.0 by 4.0–5.7 μm
Saksenaea vasiformis Floccose; white coloniesFlask-shaped sporangium 20–50 by 15–45 μm; apical end has a gelatinous plug which dissolvesApophysis: flask shaped Columella: dome shaped, 11–15 μmOval, 1.4–1.2 by 2.8–4.2 μm
RhizoidsSporangiophore morphologyZygosporesOther
Primitive; rareTall, 450 μm long, arising from stolon; branched, often in whorls; occur between rhizoidal tuftsHeterothallic; globose to flattened, brown, rough walls, 50–80 μm in diameter; 1–5 equatorial ridges  Optimal growth at 37°C; maximum temperature of growth, 45, 48 or 52°C
Tuft of rhizoids originates from a “foot cell” at base of sporangiophoreUnbranched; 200–300 μm long ending in a “foot cell”; pigmented, thickened wall just below the apophysisNot seenGood growth at 24–42°C; sporulation improved at 37°C on nutritionally deficient medium
Tuft of dematiaceous rhizoids form from a “foot cell” at base of sporangiophore, 3–5 μm long  Short and unbranched, 25–65 μmNot seenOptimal growth at 24°C; sporulation improved at 37°C on nutritionally deficient medium