Table 4.

Differentiating features of the Sporangiole- and merosporangium-producing Mucorales

Organism nameColony morphologyFruiting-structure morphologySporangiophore morphology
Cunninghamella bertholletiae Tall, 0.5–2 cm high; white, yellow, or graySporangiophores end in vesicles 15–59 μm wide; lateral branches produce smaller vesicles 3–30 μm wide; sporangioles produced on short, straight stalksBranched, 7–130 μm long
Cokeromyces recurvatus Low mycelium; tan to gray with concentric zones of color; radial folds form with age    Sporangiophores terminate in vesicles 13–31 μm wide; sporangioles borne on recurving stalksMostly unbranched, 300–500 μm long
Syncephalastrum racemosum Floccose mycelium 0.5–1.5 cm high; White, green, olive, gray, or almost blackSporangiophores end in a terminal vesicle (30–80 μm); tubular sacks or merosporangia containing spores originate from the vesicle surfaceBranched
Sporangiole or merosporangium morphologyRhizoidsZygosporesOther
Sporangioles are golden brown, round to oval, 6–14 by 6–11 μm; smooth- and rough-wall forms both seenPrimitive; rareHeterothallic; zygospores are brown, rough walled, and round, 35–50 μm wideGrowth between 24 and 45°C
Sporangioles are round, each containing 12–20 oval, smooth-walled sporangiosporesAbsentHomothallic; zygospores are readily produced and are round, rough walled, golden brown, 33.5–54.5 μm in diameterDimorphic, with yeast phase stimulated by anaerobiosis and 37°C incubation; yeasts are 30 to 90 μm wide, with multiple small buds similar to Paracoccidioides braziliensis
Tubular merosporangia (13–25 by 4–7 μm) contain round to oval sporangiospores 3–7 μm wide  RareHeterothallic; zygospores are rough walled, round, 50–90 μm wideThermophilic, with growth above 37°C