the rudiments of a receptacle or head; by degrees, and frequently by slow degrees,[111] the perfected structures of the plant are elaborated and spread themselves out into some of the forms mentioned above, of which the clavate is the most simple, and that with gills the most complex. The primary nucleus is formed out of simple cellular membrane, the cells of which, at first elongating, and at length uniting into little bundles, assume a fibrous appearance; sometimes these fascicular bodies effuse themselves unchanged into the substance of the receptacle, in which they spread out and are lost; at others, a transverse line makes the demarcation between the pileus and stem.[112] The last part formed in a fungus, generally, is that which bears the seed; and whenever an exception to this occurs, and the seed is formed at an earlier period than usual, nature has in this case provided three membranes, to cover and protect these delicate organs till the plant shall have attained maturity: these are the ring (_annulus_), the veil (_velum_), and the wrapper (_volva_). OF THE ANNULUS, THE VELUM, AND THE VOLVA. Of these involucra the first two are partial, the other universal. The Volva is a thick membranaceous covering, originating at the base of the fungus, which it thus connects with the earth, and furnishes, during its fœtal life, with the means of support and nourishment. When this has ceased, and the plant has quitted its wrapper, if this still adhere to the base of the stalk, it is styled manifest (_manifesta_), but if there be no traces of it left, obliterated (_obliterata_). It is _free_ when it can be easily detached, and _congenital_ when it cannot without laceration. In funguses with bulbous roots it is congenital, in those without bulbs it is free. All funguses that have a volva are of course _volvati_, but as this organ exists in many only so long as they are underground, mycologists are agreed to restrict the term to such alone as retain it afterwards. _The Ring._—This, which differs considerably in form, substance, and in its attachments, is composed either of a continuous sheet of membrane or else of a number of delicately-spun threads, resembling a spider’s web,[113] which in either case passing from the margin of the pileus to the corresponding upper portion of the stem, give way as the plant expands, and either festoon for a season the margin of the cap, or encircle the stalk with a ring. The marginal remains of the Annulus are extremely fugacious, but the ring round the stalk, though generally transitory, is sometimes persistent; it is _superior_ or _descending_ when originating from the summit of the stem, it descends outwards and downwards to form connections with the rim of the pileus; _inferior_ or _ascending_ when, coming off from that portion of the stalk which is below the pileus, it ascends to attach itself to this. In a few cases the ring is partly membranaceous and partly composed of radiating arachnoid threads.