Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Strophariaceae
From April through to the first heavy frosts, a walk in mixed woodland rarely fails to reveal Sulphur Tufts fruiting on fallen trees, decaying stumps or, occasionally, hollow trunks of living trees.
This wood-rotting fungus is not a fussy feeder it tackles deciduous hardwoods as well as conifers apparently with equal relish, although it is most effective in rotting broadleaf trees (hardwoods), which generally have a higher cellulose content and rather lower lignin content than conifers.
Sulphur Tuft fungi (in the USA the spelling in common use is Sulfur Tuft) are gregarious and tend to appear in large groups so tightly packed that the caps are unable to expand regularly. The tuft shown on the left is one such example; these jostling fruitbodies were growing beside the stump of a dead conifer, their mycellium having invaded the root system.
Displays of Sulphur Tufts can recur on large stumps for two or three years in succession before the timber is reduced to its hard core of lignin, at which point other lignin-eating fungi move in to finish it off.
Very common in Britain and Ireland, Hypholoma fasciculare occurs also across most of mainland Europe, where it is most prevalent in northern and central countries. This wood-rotting species is common also in North America.
Described scientifically in 1778 by British botanist and mycologist William Hudson (1730 - 1793), this common wood-rotting mushroom was initially given the name Agaricus fascicularis. (Most gilled fungi were initially placed in a giant Agaricus genus, now redistributed to many other genera.) Its current base name, Hypholoma fasciculare, dates from 1871, when Paul Kummer transferred it to the genus Hypholoma.
Synonyms of Hypholoma fasciculare var. fasciculare include Agaricus fascicularis Huds., Pratella fascicularis (Huds.) Gray, Hypholoma fasciculare (Huds.) P. Kumm., Agaricus sadleri Berk. & Broome, Naematoloma fasciculare (Huds.) P. Karst., and Hypholoma fasciculare f. sterilis J. E. Lange.
Above: Sulphur Tuft fungi swarming over coniferl tree stumps in central France.
In 1923, J. E. Lange separated from the nominate form a variety of Sulphur Tuft which is named Hypholoma fasciculare var. pusillum J. E. Lange; it is a rare find in Britain. Synonyms of this variety of Sulphur Tuft include Naematoloma capnoides var. pusillum (J. E. Lange) Courtec., and Psilocybe fascicularis var. pusilla (J. E. Lange) Noordel.
Hypholoma, the genus name, means 'mushrooms with threads'. It may be a reference to thev thread-like partial veil that connects the cap rim to the stem of young fruitbodies, although some authorities suggest that it is a reference to the thread-like rhizomorphs (root-like bundles of mycelial hyphae) that radiate from the stem base.
It hardly needs mentioning that the common name Sulphur Tuft is a reference to the bright sulphur-yellow colour of the caps of these fungi combined with their habit of growing in tightly bunched tufts.
The specific epithet fasciculare comes from the Latin word fasces, a bundle of rods bound around an axe-head used by magistrates in ancient Roman magistrate as a symbol of authority and power. Fascism comes from the same source, implying a small group (or bundle) with imposed and centralised authority and power.
Very variable in cap size, the Sulphur Tuft fungus, Hypholoma fasciculare, is inedible with a very bitter taste. In Britain and Europe Hypholoma fasciculare has been linked to severe cases of poisoning and most probably at least one death; however, there seems to be little published information about the 'Fasciculol' toxins involved. Any suggestion that this species is edible should be treated with great scepticism - and in any case its extremely bitter taste ought to be quite effective as a deterrent for people with any taste buds at all.
Although only very rarely fatal, poisoning by Hypholoma fasciculare is occasionally reported and it can result in severe symptoms, including not only stomach pains and nausea but also temprary paralysis and distorted vision. Sulphur Tuft fungi have such a bitter taste, however, that only the most determinied fungiphage is likely to want to eat them. Concealed within a meal of otherwise edible fungi it is possible that the bitter taste of Sulohur Tusts could go unnoticed. There is a delay of typically five to ten hours between ingestion of these fungi and the appearance of symptoms of poisoning.
Sulphur yellow, often tan towards the centre of the cap; convex or slightly umbonate, with dark velar remnants attached to the cap margin. 2 to 7cm in diameter.
The cap flesh is sulphur yellow and quite firm.
The crowded adnate gills of the Sulphur Tuft are initially sulphur yellow, becoming olive-green and progressively blackening as the spores ripen.
Stems of Hypholoma fasciculare are more or less concolorous with the cap, but rather browner towards the base; 5 to 10 mm in diameter, usually curved with length 5 to 12cm.
Ellipsoidal, smooth, 6-7.8 x 4-4.5μm; with a small germ pore.
Hypholoma fasciculare has a mushroomy but undistinctive odour and a very bitter taste. (If you taste this mushroom do not swallow any; please remember that it is inedible and capable of causing very unpleasant stomach upsets.)
Habitat & Ecological role
Sulphur Tuft is saprobic, feeding on stumps, felled trunks and other dead wood from broad-leaf trees and less commonly conifers. If you see tufts apparently growing in grass it is a certainty that buried roots or other timber and lying just beneath the soil surface. As the root systems of many broadleaf trees extend well beyond the leaf canopy, so also the Sulphur Tuft fungus can fruit quite a long way from the trunk of the decaying tree on which its mycellium is feeding.
All through the year in Britain, but most abundant from June to November.
Hypholoma capnoides, Conifer Tuft, has pale grey gills with no hint of green.
Above: Only a small mossy mound in the forest floor remains to show that a tree was once here, but Sulphur Tuft mushrooms still continue to find something to feed upon. Tree stumps can bear fruitbodies of Hypholoma fasciculare for several years in succession.
Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.
Funga Nordica: 2nd edition 2012. Edited by Knudsen, H. & Vesterholt, J. ISBN 9788798396130
BMS List of English Names for Fungi
Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008
Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi.
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