200 THE VICTORIAN NATURALIST. 



they are separated into a distinct family which lichenologists call 

 Collemacei, from the Greek colla, glue or gelatine. The rest of 

 the flattened lichens are called Phyllodei, leaf-like, from the 

 Greek phyllos, a leaf. 3. Thirdly, among the close-clinging 

 lichens, a large number are distinguished by the apothecium, 

 or fruit, being enveloped in a sort of minute nut, more or less 

 immersed in the thallus; on account of which lichenologists 

 separate them into a family, under the name of Pyrenodei, 

 kernel-like, from the Greek pyren, a kernel. The rest of the 

 close-clinging lichens are gathered into a family called 

 Placodei, plate-like or flat, from the Greek plax, a plate. 

 Besides these six families, there are a number of lichens whose 

 apothecia thrust out their ripe spore vessels like black dust 

 on to the surface of the fruit. I remember being much puzzled 

 and astonished when I first gathered one of this family. The 

 profusion of black dust which came from its lacerated bag-like 

 apothecia made me think at first that I had come upon some 

 strange fungus. This family is called Epiconiodei, from the 

 Greek epi, upon, conios, dust. 



These families are arranged by Dr. Nylander, the greatest 

 modern lichenologist, according to their relation to the algae on 

 the one hand and to the fungi on the other, in the following 

 order : — 



1. Collemacei, gelatinous. 



2. Epiconiodei, dust fruited. 



3. Cladodei, shoot-like. 



4. Ramalodei, branch-like. 



5. Phyllodei, leaf-like. 



6. Placodei, plate-like. 



7. Pyrenodei, kernel fruited. 



We need only, in order to complete Dr. Nylander's classifica- 

 tion, to separate the first of these into a distinct family, and 

 insert between it and the rest a strange family, of which only 

 two species are known, called by him Myriangiacei, from the 

 Greek inyrios, many, and angeion, a vase or vessel. The 

 remainder he classes together under the family Lichenacei, 

 or lichens proper. 



The beginner must not imagine that this classification is so 

 distinct that he can always see at a glance what family of lichens 

 his specimen belongs to. Nature shows very imperceptible 

 gradations between species, or genera, or families — particularly, 

 I think, among lichens. And each genus has its relation to 

 others so close as to necessitate in many cases careful and 

 minute examination to come to a sure conclusion. And, 

 indeed, we often cannot come to a sure conclusion at 

 all. Every lichenologist has many specimens laid apart 

 for further examination, which he cannot yet refer to any 



