Sparassis crispa (cauliflower fungus)
Cauliflower fungus grows parasitically on the roots of conifers, and can be recognised by its distinctive, whitish to pale buff, much-lobed fruitbodies, which have been considered to resemble a cauliflower.
About this species
Sparassis crispa is the most common, and best known, species of the genus and is found throughout much of Europe and eastern North America. Its fruitbodies have a rooting base, arising from the roots of the host tree, though they may occasionally occur on the trunk itself or even on dead stumps. They are edible but should be thoroughly washed first to remove grit and dirt harboured amongst the lobes, and should be well-cooked. Cauliflower fungus is widely collected and is also cultivated (especially in Japan) for its culinary value.
Like most fungi, fruitbodies of Sparassis crispa can vary in size. Most are around 15 – 20 cm across, and when fresh may weigh over 5 kg. However, heavier specimens up to 30 cm or so in diameter can sometimes be found and occasionally even larger specimens have been recorded. One, found in southeast France in 2000, was reported in the Los Angeles Times to weigh a remarkable 63.4 pounds (28.8 kg), more than double the previous record! It is reported that the finders had to use a jacket to move it to their car, and that the specimen was to be frozen for exhibit at mushroom fairs.
Geography & Distribution
Cauliflower fungus is widespread and fairly common in Britain, though apparently more scarce in Scotland and Ireland. It is found in much of Europe, but is rarer in some areas, and rated as Vulnerable in Belarus. It is also known from eastern North America, and reported from Asia and Australia, but these reports may represent a different species.
The fruitbodies of Sparassis crispa are cream to pale buff, often with yellowish tints when dry, and with white flesh. They arise from a rooting base, and are much branched, comprising compound lobes forming a dense cauliflower-like mass of up to 30 cm across and 25 cm high. The lobes are flattened or crisped, or sometimes more spoon-shaped, and rather brittle. The wavy lobes are mostly 1 - 2 cm wide, but occasionally wider, with rounded tips. The edges can be entire (smooth) or occasionally somewhat ragged or irregularly toothed. The lobes are fertile on the lower, or sometimes both surfaces. The basidia (spore-producing organs) are 45-60 x 6-7.5 μm, narrowly club-shaped, and 4-spored, with a basal clamp-connection. Slender sterile processes (hyphidia) are present amongst the basidia, are cylindric to rather wavy, or occasionally forked, and are 3 to 4 μm wide. The spores are colourless under the microscope, but pale yellowish in mass and are smooth, subglobose to broadly ellipsoid or ovate, and usually with a single guttule (oil-like drop inside the spore). They measure 5 – 7 x 4 – 5 μm. The flesh hyphae are interwoven, with thin or sometimes somewhat thickened walls, and are 3 – 8 μm in diameter. Inflated elements of up to 20 – 30 μm diameter and some refractive hyphae are present, and clamp connections are frequent throughout.
About this genusMore Information
The genus Sparassis was described by the Swedish mycologist Elias Fries in 1819, and includes species which have large, distinctive fruitbodies and are important root parasites of conifers and occasionally broad-leafed trees (Fagaceae). It is currently placed in its own family Sparassidaceae (Polyporales) but was once referred to the Clavariaceae, which originally included most of the so-called 'club and coral fungi'. The taxonomy of these fungi has since been greatly amended based on the microanatomy of the fruitbodies. Although almost worldwide in distribution, Sparassis is a small genus and includes no more than about eight species, the delimitation and range of which require further study. These occur mainly in the northern hemisphere, but at least one as yet undescribed species is known from Tasmania.
Delimitation of species in Sparassis has been very confused, due mainly to similarity in the form of their fruitbodies. In Britain a second species, S. simplex, also occurs, but is less common than S. crispa. It differs in having broadly spathulate (spoon-shaped) lobes, in lacking a rooting base, and in spore and hyphal characters. Elsewhere in Europe is found another species, S. brevipes, which is similar in form to S. simplex but differs in its somewhat smaller spores and hyphal structure. It is not yet confirmed as occurring in Britain. In North America the mainly European S. crispa is rare and present only in eastern USA. In the past it had not been distinguished from the similar and evidently more common S. radicata. The latter, found in western North America, is remarkably similar in form and ecology to S. crispa, but differs in having lobes arising from a common base rather than from a branched rooting base. Also in North America is S. spathulata, with broad, distinctly zonate, spathulate lobes and larger spores than S. crispa but rather similar to the European S. brevipes. Sparassis latifolia, a recently described Asian species, is also similar in form to S. crispa, but has larger, broader lobes, which arise from a common base. Finally, another as yet unnamed and evidently rare species has been recently collected in Tasmania.
Threats & Conservation
No specific threats are known, and the species is not considered of conservation concern in Britain. However, it is scarce in parts of Europe and is listed as Vulnerable in the Red Data Book of Belarus.
- Insect breeding
Cauliflower fungus is edible. The fruitbodies should be collected in good, fresh condition and thoroughly washed to remove dirt and grit from amongst the lobes.
The fruitbodies have been shown to have anti-tumour properties, and to contain chemicals which may stimulate the immune system and inhibit growth of the 'superbug' MRSA (methicillin-resistant Staphylococcus aureus).
As with many fleshy fungi, the fruitbodies are used for breeding by various insects, notably flies (Diptera) including some species of Leia and Mycomya (Mycetophilidae), Lycoriella (Sciaridae), and Spelobia (Sphaeroceridae), though none seems to be specific to Sparassis. The fruitbodies are sometimes eaten by rabbits.
Cauliflower fungus is commercially cultivated in Japan and China, and also in the United States, where the culture medium and methods are the subject of a US patent. However, it has reportedly also been grown on steam-treated coniferous sawdust.
The cauliflower fungus at Kew
Sparassis crispa can occasionally be found in the gardens at Kew, where it has been recorded in association with Cedrus, Pinus and Pseudotsuga species. It normally fruits in autumn (September to November).
Collections of Sparassis crispa and related species from throughout their range worldwide are preserved in the Kew Mycology Herbarium, one of the behind-the-scenes areas of Kew. These specimens are made available for study by bona fide researchers by appointment.
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