Byssus

Byssus (Gr., 'a fine flaxen or silky substance'), a genus established by Linnæus to include some of the lowest and most obscure forms of vegetation, and defined as having a substance like fine down or velvet, simple or feathered. Botanists have sometimes ranked it among Algae, sometimes among Fungi; it has been made the type of a group Byssaceæ, and placed among Lichens. Some were wont to regard this group as entitled to the rank of a distinct order, 'comprehending the filamentous fungi found in cellars, and similar plants;' others again have rejected the genus as altogether spurious. It is still retained by some systematists, but as a mere provisional limbo to include a number of gossamer-like mycelial forms of moulds which occasionally appear in damp places, and disappear without showing any signs of fructification by which to determine their true nature and affinities. The progress of research has greatly reduced this vague alliance, some forms having been recognised as algal, others as fungal in nature; and its disappearance from our lists may thus be regarded as a mere question of time.