Cauliflower Mushroom
Sparassis crispa
Also called wood cauliflower, brain fungus, noodle mushroom
A large cream-coloured rosette of flattened, crimped, ribbon-like lobes that grows at the base of conifers, resembling a cauliflower head or a bath sponge.
Overview
The Cauliflower Mushroom is a large, rounded, cream to pale ochre mass built from dozens of flattened, wavy, ribbon-like lobes packed tightly together. From a distance it can look like a discarded sponge, a bundle of egg noodles or a giant brain sitting at the foot of a pine, and it can weigh several kilograms.
Sparassis is a small genus whose members are unusual in being placed with the polypores, in the order Polyporales, despite having no pores at all. Their spore-bearing surface is smooth and covers the underside and edges of the flattened lobes. This makes them structurally intermediate between bracket fungi and the branched coral fungi they superficially resemble.
Species limits within the genus depend on lobe shape and host. S. crispa has narrow, tightly crisped, strongly wavy lobes and is a conifer specialist, while its relatives have broader, flatter, more spatula-like lobes and tend toward oaks and other hardwoods.
How to identify it
Fruiting body
A globose to broadly cushion-shaped mass 10–50 cm across, arising from a short, thick, root-like base buried at the foot of a tree. The body is built of numerous flattened, ribbon-like or leaf-like lobes, each 1–3 cm wide, densely crisped and wavy along their edges and arranged in a rosette so that the whole structure resembles a cauliflower curd. There is no cap, no gills and no pores.
Colour and texture
Fresh specimens are pale cream, white or pale butter-yellow, darkening to ochre, tan and finally reddish-brown from the lobe margins inward as they age or dry. The texture is elastic and slightly rubbery when young, becoming brittle in old specimens. The fertile surface is smooth and coats the underside of each lobe.
Base, flesh & spore print
The rooting base is tough, whitish and often stained brown, and it may extend a considerable distance into the soil to the root it is attached to. Flesh is white throughout and does not change colour when cut; the smell is pleasant and slightly sweet or aromatic. The spore print is white to pale cream, from small, smooth, ellipsoid spores.
Where and when it grows
Sparassis crispa fruits at the base of living conifers or from the ground directly over their roots, and occasionally on stumps. Scots pine is the classic host in Europe, with other pines, spruce, larch and Douglas fir also used; it is a fungus of pine plantations, sandy pine heath, and mixed conifer woodland.
It appears from late summer to late autumn, often in the same spot for a run of years, since the mycelium persists in the root system. It is widespread across Europe and temperate Asia, and closely related species occupy similar niches in North America. Fruiting bodies are conspicuous and long-lasting, remaining recognisable for two to three weeks.
Ecological role
The fungus is a parasite and saprophyte causing a brown rot in the roots and butt of conifers. It enters through root wounds, decays the heartwood of the root system and lower trunk, and continues to fruit from the same root plate for years, sometimes long after the host has been felled. Because the decay is concentrated in the base and roots, an infected tree may show little crown dieback until it becomes unstable.
In plantation forestry this makes it a butt-rot organism of some importance, but ecologically it is part of the natural turnover of conifer stands, hollowing root systems and returning heartwood carbon to the soil. Its brown-rot residue — dry, crumbly, cubically cracked wood — is a persistent soil component that holds water and supports invertebrates and fine tree roots.
Similar species
Sparassis spathulata (and the closely related S. americana) is the main confusion: it has broader, flatter, more spatula- or fan-shaped lobes that are often marked with faint concentric zones, and it associates with oaks and other hardwoods rather than pines. Sparassis brevipes has thicker, tougher, less crisped lobes and a shorter base, and again tends toward broadleaved hosts.
Ramaria species and other coral fungi are built from rounded, upright, repeatedly forking branches rather than flattened crisped ribbons, and they stand up from the ground instead of forming a dense rosette. Tremella and other jelly fungi are gelatinous and translucent, collapse when handled, and grow on wood above ground rather than from a rooting base at a tree's foot.