In the young state of the Mushroom, the fructification appears as little knobs upon the spawn or mycelium. Upon cutting these through perpendicularly, the cap and stalk are found to be enclosed in a skin or wrapper, called the _vol´va_ (_volva_, a wrapper), and the margin of the cap is continuous with the surface of the stalk, the connecting membrane forming the _veil_, or _vélum_ (_velum_, a veil). As the Fungus grows, the cap rises and bursts the volva, which withers and disappears; and the veil is torn through, the portion remaining in connexion with the stalk encircling it as a collar or ring (_an´nulus_). _Merúlius lach´rymans_, the Dry-rot Fungus, which belongs to the same family (Agaricíni) as the Mushroom, deserves notice from its very destructive action upon decaying timber. The filaments of the mycelium may readily be detected in the rotting wood by examining a thin section in water. The receptacle forms a yellowish-orange or brownish flattened mass, some inches in breadth, with white downy margins; and the surface exhibits folds arranged so as to form large irregular pores, instead of gills as in the Mushroom. In other families the cap and stalk appear fused together and undistinguishable; or the fructification assumes the form of the cap or the stalk only, and the hymenium does not form gills. Thus in the family Polyporei (the members of which are common on the trunks of trees and on rotten posts, and some of which are very large) the basidia are situated upon the inner surface of tubes immersed in the under part of the mass, their orifices forming minute pores, yet visible to the naked eye. In other families the basidia are placed upon the outer surface of a club-shaped or branched receptacle (Clavarini), or upon external prickle-like points (Hydnei), &c. In the family Tremellini the receptacle forms a gelatinous mass, and the basidia are situated upon its surface, terminating the filaments of which it is composed. One species, _Dacrymy´ces stillátus_, is very common on fir posts in the winter and spring, forming little roundish, yellowish-orange, cushion-like masses. GASTEROMYCE´TES (γαστἠρ, belly, hollow, μὑκης, fungus).--This order of Fungi, which contains the Puff-balls and many others not readily procured, must be very briefly noticed. The spores are contained in a capsule or perid´ium (πηρἱδιον, a little bag) which is often of large size, and are situated upon a hymenium forming folds, partitions (septa), or a lattice-work. A small species, _Physárum album_ (Pl. VII. fig. 3), is often found growing upon rotten stems of plants and decaying sticks. The capsules are minute, grey, brittle, and black within, from the presence of the spores (fig. 4), which are lens-shaped, and arise from the ends of short filaments.