Megacollybia platyphylla - Whitelaced Shank

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

With a dark cap covering pallid gills, this is another tricky species to identify in situ, but its identity is at once betrayed if you excavate the base of the stem. The Whitelaced Shank has white... well, 'laces' is actually quite a good description for the stringy mycelial fibres that extend from the stem base for some considerable distance into the substrate timber or wood-rich humus of the forest floor. (See the picture in the 'Stem' identification characteristics, below.)

This is the only species in the genus Megacollybia that is recorded from Britain. Megacollybia platyphylla occurs mainly in deciduous broadleaf woodland and is a saprotroph (feeding on rotting wood and other organic vegetation).

Identification Guide

	Cap 6 to 14cm across; convex, not flattening completely but often developing a slight central depression with a small umbo; smooth and dry; grey-brown with radial streaks. In dry weather the caps of this mushroom sometimes split radially at the margins.
Gills	Sinuate or adnexed to stem; white, turning cream with age; crowded and very broad (platyphylla means literally 'broad leaves'). On older species the gills become irregularly wavy.
	Stem 5 to 15cm long and 0.6 to 1cm dia.; base often rooting and with long white rhizomorphs (see left) attached; white, covered in grey-brown fibrils, paler at apex; no ring.
Spore print	White.
Odour/taste	Not significant.
Habitat	Saprobic; solitary or in small groups on and near deciduous hardwood trunks, branches or woody debris (rarely on conifer timber), or arising from the forest floor from from buried wood.
Season	June to November.
Occurrence	Fairly common.
Similar species	More than thirty species in the Melanoleuca genus are recorded from Britain and Ireland, and most have brownish caps and white gills; separating them is a task for specialists. Many of them are very rare finds, whereas the Common Cavalier is by far the most widespread and abundant member of the group.