The only species of the Hydnaceae described here are in the genus Hydnum. In this genus the fruiting surface is on spine, or awl-shaped processes, which are either simple or in some cases the tips are more or less branched. The plants grow on the ground or on wood. The species vary greatly in form. Some are provided with a more or less regular cap and a stem, while others are shelving or bracket shaped, and still others are spread out over the surface of the wood (resupinate).

Hydnum coralloides Scop. Edible. - Among the very beautiful species of the genus Hydnum ,is the coral one, Hydnum coralloides. It grows in woods forming large, beautiful, pure white tufts on rotten logs, branches, etc. The appearance of one of these tufts is shown in Fig. 195. There is a common stem which arises from the wood, and this branches successively into long, ascending, graceful shoots. The spines are scattered over the entire under side of these branches and hang down for 3-6 mm. They are not clustered at the ends of the branches, as in the bear's head hydnum, and the species can be easily distinguished by giving attention to the form of the branching and the distribution of the spines on the under side of the branches. Figure 195 represents a plant collected at Ithaca, and it is natural size. They grow, however, much larger than this specimen. The species is widely distributed, and not uncommon. It is excellent for food.

Figure 195

Hydnum coralloides. Entirely white (natural size). Copyright.

Hydnum caput-ursi Fr. Edible. - This plant is also a beautiful one. It is more common than the coral hydnum so far as my observation goes. It is known by the popular name of "bear's head hydnum" in allusion to the groups of spines at the ends of the branches. It occurs in woods with a similar habit of growing on trunks, branches, etc. This plant also arises from the wood with a single stout stem, which then branches successively, the ends of the branches having groups of long pendant spines appearing like numerous heads. Sometimes the spines on the top of the group are twisted or curled in a peculiar way. Large tufts are sometimes formed, varying from 12-20 or more centimeters in diameter. Figure 196 is from a plant collected at Ithaca.

Figure 197

Hydnum erinaceus. Entirely white (natural size, often larger).

Hydnum caput medusae Bull. Edible. - The medusa's head hydnum is a rarer species than either of the above in this country. It forms a large, tubercular mass which does not branch like the coral hydnum or the bear's head, but more like the Satyr's beard hydnum, though the character of the spines will easily separate it from the latter. The spines cover a large part of this large tubercle, and hang downward. The plant is known by the additional character, that, on the upper part of the tubercle, the spines are twisted and interwoven in a peculiar fashion.

Hydnum erinaceus Bull. Edible. - This plant is sometimes called "Satyr's beard." It grows on dead trunks in the woods or groves, and is often found growing from wounds in living trees. It forms a large, tubercular mass which does not branch. The spines are very long and straight and hang downward in straight parallel lines from the sides of the mass. The spines are from 1-2 cm. or more long. Figure 197 represents one of the plants, showing the long spines.

Hydnum repandum L. Edible. - This plant is not uncommon, and it is widely distributed. It grows usually in woods, on the ground. It varies greatly in size, from very small specimens, 1-2 cm. high to others 10-12 cm. high. The cap is 2-18 cm. broad, and the stem 6-12 mm. in thickness.

It is entirely white or the cap varies to buff, dull yellow reddish or dull brown. It is very brittle, and must be handled with the utmost care if one wishes to preserve the specimen intact. The pileus is more or less irregular, the stem being generally eccentric, so that the pileus is produced more on one side than on the other, sometimes entirely lateral at the end of the stem. The margin is more or less wavy or repand. The spines are white, straight, and very brittle. The stem is even or clavate. Figure 198 is from plants collected at Ithaca during August, 1899, and represents one of the large specimens of the species. In one plant the pileus is entirely lateral on the end of the long clavate stem, and is somewhat reni-form, the stem being attached at the sinus. In the other plant the stem is attached near the center. This species is considered one of the best mushrooms for the table.

Hydnum imbricatum L. Edible - This is a very variable species both in size and in the surface characters of the pileus. It occurs in woods, groves, or in open places under trees. The plants are 3-7 cm. high, and the pileus varies from 5-15 cm. broad, the stem from .5-2.5 cm. in thickness. The pileus is convex and nearly expanded, fleshy, thinner at the margin, regular or very irregular. The color is grayish in the younger and smaller plants to umber or quite dark in the larger and older ones. The surface is cracked and torn into triangular scales, showing the whitish color of the flesh between the scales. The scales are small in the younger plants and larger in the older ones. Figure 200 is from plants collected at Ithaca, and the pileus in these specimens is irregular. The species is edible, but bitter to the taste.

Plate 78, Figure 198

Hydnum repandum. Cap whitish or yellowish, or pale yellowish brown; spines whitish or yellowish (natural size, often smaller). Copyright.

Plate 79, Figure 199

Hydnum putidum. Caps whitish then buff, then brownish or nearly black in older parts, edge white (natural size). Copyright.

Figure 200

Hydnum imbricatum. Caps brownish, spines whitish (natural size, often larger).