Black Witches' Butter :

Black Jelly Roll, Warty Jelly Fungus
Exidia glandulosa

This black, gelatinous fungus grows alone or in rows on dead hardwood from fall through winter.

Appearance

Olive-black to black, gelatinous mass of convoluted folds, resembling a brain, about 1-2 cm. wide and when fused, 10-20 cm. long and 3-5 cm. wide
Forms black crust when dry
Spore print whitish
Without a stipe (stem)
Grows alone or in rows

ID Tips

May be confused with warlock’s butter (Exidia nigricans), which is virtually indistinguishable from black witches’ butter
- More study is needed to confirm identification of California species

At Edgewood

About

Basidiomycetes – a major lineage of fungi that usually produce spores within basidia (club-like structures)
Found from fall through winter
Saprotrophic – grows on dead hardwood (e.g. oaks)
Edibility (San Mateo County Parks prohibits removal of any natural material)
- Edible
- Unless you are an expert, do not pick and consume wild mushrooms

Fun Facts

Black witches’ butter belongs to a group of fungi known as jelly fungi, since many have gelatinous basidiocarps (fruit bodies) which are well adapted to periodic drying
- About 20 species in this group have been reported in California

Learn More

References

Desjardin, D.E., M.G. Wood, and F.A. Stevens. 2016. California Mushrooms: The Comprehensive Identification Guide. Timber Press, Portland, Oregon.

Wood, M., and F. Stevens. 2020. Exidia glandulosa. The Fungi of California. MykoWeb.