4 ' KANSAS CITY REVIEW OF SCIENCE. 



Another instance of polymorphism in fungi is found in a species of Isaria, 

 that is parasitic on the Bramble moth — Bombix Rubi — which has several distinct 

 periods and modes of fructification. This fungus in passing from one stage of its 

 growth to another, not only changes from one species and genus to another, but 

 it actually leaps over the chasm that separates one family from another — starting 

 as a member of Hyphomycetes and ending as a member of the Ascomycetes 

 family. Numerous other cases are now known and many others are suspected 

 in which fungi that have been named and classed as entirely distinct plants are 

 but different forms of the same species. So far as we yet know these different 

 forms are but steps in regular cycles that invariably return to the original start- 

 ing point whence again to start on their regular round of transformations. 



Our present knowledge does not warrant the conclusion that any of these 

 changes are the progressive steps from lower to higher forms of vegetable organ- 

 isms. The classification qf fungi is based on the mode of fructification. Ac- 

 cording to this all fungi are embraced in two grand divisions or sections, accord- 

 ingly as the reproductive germs are produced in cysts or capsules, or without any 

 such enclosing organs. In this last the reproductive germs, called spores, are 

 produced on spicules. This section has been called Sporifera from these facts. 

 The other division is termed Sporidifera, in which the fruiting germs are pro- 

 duced in cells or cysts, and are termed Sporidia. To the first of these sections 

 belong four families, two of which are furnished with a hymenium or spore-bear- 

 ing surface, while the other two are destitute of this. Of the hymeniferous fam- 

 ilies one — the Hymenomycetes — has its hymenium on an exposed surface. Of 

 this family the common mushroom — Agaricus — with its expanded pileus and 

 radiating gills, is a familiar example. In the second family — Gasteromycetes — 

 though a hymenium is present, it generally remains inclosed in a peridium, or 

 outer investing membrane, till the spores are nearly or quite mature, when, by 

 the rupture of the peridium, the spores are liberated and discharged into the air 

 as fine dust. The common Puff-ball (Lycoperdon,) of the meadow is a well- 

 known example of this mode of fructification. Of the two families, belonging to 

 sporifera, that are destitute of a hymenium, the first to be noticed is the Con- 

 iomycetes, which is noted for the abundant development, in its advanced stages, 

 of dusty spores. So great is the predominance of the reproductive system of 

 fungi belonging to this family that at maturity nearly the whole substance of the 

 plant seems to be converted into these spores. In the Hyphomycetes, the second 

 family of this division, it is the spore-bearing threads or filaments that are the 

 most noticeable for their abundance. 



To this family belong that numerous class of low forms of fungi known as 

 moulds. To these two families belong some of the most injurious species with 

 which we are acquainted. In the first one we find that series of parasitic fungi 

 that prove so deleterious to living plants, the Puccinia, Uredo and ^cidium. 

 To these belong the various rusts and smuts of our grain fields. 



To the second of these families belong the Mucedines, a single genus of 

 which, the Peronospora, has proved the most destructive to living plants of any 



