In the wild, they appear in the late autumn on scars on trees or on falling logs. It prefers maple, oak, sycamore and walnut trees. Though the “spines” are very soft, the base that is attached to the tree is very tough, and needs to be cut off with a knife.
They grow well in the wild throughout North America. In the UK, they are classed as an endangered species, so collection from the wild is not advised.
Commercially, they are now cultivated on hardwood chips and logs, and on sawdust. They grow very quickly in commercial cultivation and are ready to harvest in a week.
They are white and firm when young, but yellow and softer as they age. When fully-grown, they will be 4 to 8 inches wide (10 to 20 cm.) Unlike many other mushrooms which improve in taste as they mature, this one turns sour-tasting as it matures so it must be eaten very young.
They have a mild taste and rubbery flesh, like calamari.
Buy ones that still have the tips of their spines quite white. If they are yellow, the taste is starting to go.
Must be cooked before eating. Not for eating raw, owing to the texture. Cooks up firm and chewy.