Massive mushroom mania

For two members of our environment team, a standard day out looking for pennywort turned into the most exciting day of their lives with the discovery of a monster mushroom.

Phillippa Baron (North East ecologist) and Siobhan Walshe (volunteer North East environmental assistant) were on Fairies Hill, a small island on the Aire & Calder Navigation between Castleford and Wakefield, when they spotted the football sized growth. The tenant, Wendy, explained that she’d found (and eaten) a number of these mushrooms on the land and couldn’t possibly eat another slice of mushroom, so she kindly let our environment team keep it.

Back in the office, the environment team identified the mushroom as a giant puffball (Calvatia gigantica), one of the world’s largest edible fungi, and within minutes their desks were surrounded by a huge crowd of people trying to catch a glimpse of the mushroom. A lucky few even managed to grab a piece to take home for tea, with recipes ranging from simply frying in oil and garlic to using the whole slice as the base of a pizza.


The reports were unanimously good, with most people thinking the giant puffball was much tastier than the average shop bought mushroom. Thankfully the environment team seemed to identify the mushroom correctly too, as everyone has (so far) survived!

Although it easily broke the record for the largest mushroom ever seen in the Leeds offices, it actually wasn’t that impressive as the largest giant puffball on record had a crazy 2.64m circumference and weighed 22kg!

Seven trillion spores

Giant puffballs are so named for their obviously large size and because when the outer wall disintegrates the spores contained inside ‘puff’ out. Their massive size is down to the number of spores inside the mushroom; as the germination rate of spores is less than 0.001% the average giant puffball contains seven trillion spores. If each spore was laid end to end they would circle the earth at the equator, and if each of those spores grew into a giant puffball then they would reach to the sun and back more than twice!

Giant puffball mushrooms that are white are actually one of the safest mushrooms to forage for, as (unlike most mushrooms) they don’t have a poisonous lookalike. They’re mostly found in meadows and grasslands, with the white stemless mushrooms fruiting in late summer to early autumn.

Marshmallow-like consistency

The mushrooms should be eaten whilst they’re still white, and when cut in half they should have a marshmallow-like consistency with no signs of discolouration or gills. Giant puffballs also have a range of other uses, including on cuts and scratches as the flesh of the giant puffball is a good coagulant.

The flesh of the mushroom is sometimes used to calm bees in a beehive, as when burnt the fumes have a slightly anaesthetic effect. Giant puffballs even contain a substance called calvacin that has been shown to reduce cancerous tumours!

Last date edited: 15 November 2013

About this blog

The environment team

The Canal & River Trust has top team of committed experts and enthusiasts, who help to protect our waterway environment and improve it for both people and nature. Follow this blog to find out more about the hugely varied work they carry out.

See more blogs from this author