The veil remains firm for a time, but it is finally torn by the expanding pileus, and its remnants persist on the cap and stem in the form of various appendages, whose character depends on the character of the veil. In _Cortinarius_ the veil is made up of delicate threads extending radially from the stem to the margin of the cap without forming a true membrane. From its resemblance to a spider's web such a veil is said to be _arachnoid_. At maturity mere traces of it can be found on the stem. In many genera the veil consists of a delicate membrane which tears away from the stem and hangs in flakes to the margin of the pileus. In these cases the veil is _appendiculate_ (Fig. 248). Frequently it is so delicate that no trace of it remains on the mature plant. Where the veil is well developed it usually remains on the stem as a _ring_ or _annulus_ which becomes free and movable in species of _Lepiota_ (Fig. 242) and _Coprinus_, or forms a hanging annular curtain in _Amanita_, or a thick, felty ring in _Agaricus_, etc. In some plants (species of _Lepiota_) the annulus is continuous with the outer cortex of the stem, which then appears as if it were partially enclosed in a sheath, with the annulus forming a fringe on the upper end of the sheath, from which the apex of the stem projects. No reference is here made to the _volva_, which encloses the entire plant, and which is described in connection with the genera in which it occurs. The few typical characters described here will help the student to become familiar with terms applied to them. In nature, however, typical cases rarely exist, and it is often necessary to draw distinction between differences so slight that it is almost impossible to describe them. Only by patient study and a thorough acquaintance with the characters of each genus can one hope to become familiar with the many mushrooms growing in our woods and fields. CHAPTER XXIV. ANALYTICAL KEYS. By the Author. CLASS FUNGI. SUB-CLASS BASIDIOMYCETES.[F] Plants of large or medium size; fleshy, membranaceous, leathery, woody or gelatinous; growing on the ground, on wood or decaying organic matter; usually saprophytic, more rarely parasitic. Fruiting surface, or hymenium, formed of numerous crowded perpendicular basidia, the apex of the latter bearing two to six (usually four) basidiospores, or the basidiospores borne laterally; in many cases cystidia intermingled with the basidia. Hymenium either free at the beginning, or enclosed either permanently or temporarily in a more or less perfect peridium or veil. Basidiospores continuous or rarely septate, globose, obovoid, ellipsoidal to oblong, smooth or roughened, hyaline or colored, borne singly at the apex of sterigmata.