Web Mold

Web Mold, also called Troll Doll Fungus, is a parasitic mold that grows on fungi. It occurs in Europe and North America. It occurs in the United States and Southern Canada east of the Great Plains and in the Pacific Northwest.

Web Mold is found from May through October in woodlands, wetlands, and lawns. It has been recorded growing on more than 65 genera of mushrooms in the United States. It affects fleshy mushrooms that are dead, dying, in decline, or in poor health. It is presumed to have a parasitic relationship with fleshy fungi, but further studies are needed to confirm its parasitic mechanisms.

Web mold appears as a fuzzy growth consisting of a vegetative base (mycelium) with numerous upright stalks (sporangiophores). Each sporangiophore has a minute spore-bearing structure (sporangium) at the tip.

The mycelium is a dense mat of fungal threads (hyphae). The hyphae are 3-60 µm broad and tube-like, with no cross-walls (septa) except at the base of the sporangiophores.

The sporangiophores are erect, 1⁄64″ to 1 9⁄16″ (0.5 to 40.0 mm) high, and up to six times forked (dichotomously branched). They are colorless (hyaline) at first, but a mass of them appears white or grayish to the naked eye or in reflected light. As they mature they turn yellow to pale brown.

The sporangia are globe-shaped or irregularly globe-shaped, and 50-150 µm broad. They are yellow but appear gray to the naked eye or in reflected light.

The spores (sporangiospores) are hyaline to pale brown.

Woodlands, wetlands, and lawns

May through October

Sources

24, 26, 29, 30, 77.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu, 8/15/2025).

Family
A recent phylogenetic study of the phylum Mucoromycota (Zhao, Heng et al., 2023) updated the classification framework of the phylum Mucoromycota from the class down to the generic rank. The authors erected five new families, including Syzygitaceae, which now includes the genus Syzygites.

The new family Syzygitaceae has not been universally adopted. The main reason is the newness of the study. The new classification needs time for the findings to be adopted by the broader scientific community.

Mycoportal, Mushrom Observer, Mushroom Expert place Syzygites in the family Mucoraceae.

MycoBank, GBIF, and NCBI place Syzygites in the family Rhizopodaceae.

Index Fungorum, Catalogue of Life, and iNaturalist place Syzygites in the family Syzygitaceae.

Time Lapse of Troll Doll Fungus - Syzygites megalocarpus
zaacis1

Luciearl
8/28/2019

Location: Cass County

mushrooms with white feathery lichen