HYDNUM, in botany: A genus of the natural order of fungi, belonging to the cryptogamia class of plants. The fungus is echinated or prickly on the under side. One of the species, named the Imbricatum, is a native of Britain, and is found in woods. It hath a convex hat, tiled, standing on a smooth pillar, of a pale flesh-colour, with white prickles. It is eaten in Italy, and is said to be of a very delicate taste.