Mud Cup
Peziza limnaea
The Mud Cup is a specialized ascomycete fungus within the Pezizaceae family. It produces cup- to bowl-shaped fruiting bodies, typically olive-brown to dark brown, which preferentially colonize bare, moist mud at pond edges or in ditches. As a saprobic organism, it plays an important role in decomposing organic matter in amphibious habitats. The species is closely tied to fluctuating pioneer sites and primarily appears in late summer and autumn.
Details
Identification
Fruiting bodies 1–5 cm wide, cup-shaped; inner surface (hymenium) dark olive-brown to black-brown; outer surface scurfy-granular; flesh brittle; spores elliptical (approx. 18-22 x 10-12 µm) and finely warted.
Social behavior
Usually grows gregariously in groups on the mud.
Diet
Saprotrophic; gains energy by decomposing dead organic material in the mud.
Overwintering
Persistence as mycelium in the soil or through spores.
Ecology
Ecological role
Primary decomposer in the littoral zone; contributes to nutrient cycling in aquatic transition areas.
Natural predators
Slugs, snails, insect larvae, and various small mammals.
Competitor species
Other hygrophilous Peziza species and soil fungi of the shore zone.
Ecosystem service
Nutrient cycle regulation through mineralization of organic deposits.
Threats
Loss of wetlands, shore reinforcement, drainage, and excessive nutrient input (eutrophication).
Scientific profile
Profile
Distinguishing features
Occurrence on bare mud; spores 18-22 x 9-11 µm, finely warted ornamentation, usually with two large oil droplets (biguttulate). Asci amyloid (blue in iodine).
Habitat
Pioneer sites on bare, moist soil, riparian zones of standing and running waters, damp forest paths.
Reproduction
Sexual spore production in asci (apothecium); eight spores per ascus.