Hymenium inferior or amphigenous (not confined to one surface), from the first definitely protuberant, spread over persistent spines, bristles, teeth, tubercles or papilla. Fries.
While the highest members of this family possess the general form of the mushroom, others, lacking a stem, recline on the back (resupinate); the lowest, without even the appearance of a distinct pileus, seem to be simply spread over the supporting body (effused). In the highest class the spines or other spore-bearing surface are inferior, i. e., below the pileus; in the others they are of course superior, i. e., above the pileus.
Of the eleven genera but two contain species of food value. Hydnum, characterized by its acute spines, embraces species which are eaten as delicacies, and Irpex, distinguished by its somewhat acute teeth growing from a ridgy hymenium, contains those which may furnish sustenance in time of need. In Caldesia, bearing spines, the texture is floccose not fleshy. Sistotrema has a pileus and a central stem, but instead of spines bears irregular flattened teeth. The remaining genera are separated by the tubercles, granules, folds, etc., which take the place of spines or teeth.
Several species of Hydnum are common to earth and wood, others are distinct in their habitats.
SYNOPSIS OF THE GENERA.
Hydnum. Page [494].
Sporophore fleshy, with a central stem or entirely resupinate, texture compact, spines acute, distinct at the base.
Caldesiella.
Resupinate; texture floccose, spines acute; spores muriculate. (No edible species reported.)
Sistotrema.