STATE PO.MOLOGICAL SOCIETY. 53 



SOME PLAXT DISEASES AXD THEIR REMEDIES. 

 Professor W. 31. Muxsox, State College, Oroao. 



All known plants are divided into two great classes — Phienogams 

 or flowering plants ; and Cryptogams or non-flowering plants. The 

 former are characterized by the production of flowers and seeds ; 

 and as a rule are provided with a green coloring matter — chlorophyll 

 — through the agency of which the inorganic constituents of the 

 soil, carried upward by the movement of the sap, are combined with 

 the carbon dioxide of the air into organic compounds — starch, 

 sugars, oils, etc., essential to plant life and growth. 



All cryptogams are without flowers or seeds, but many of them, 

 as ferns, mosses, sea- weeds, etc., contain the chlorophyll necessary 

 to the assimilation of inorganic matter. One important class, how- 

 ever — the fungi — are entirely without this agent, and necessarily 

 depend for subsistence on some store of organic material, either 

 animal or vegetable. In other words, a fungus is a plant ; but 

 possessing no green coloring matter, it cannot utilize inorganic 

 matter like ordinary plants, and must live on materials already pre- 

 pared by other plants. This material may be found either in living 

 or dead plants or animals. 



That part of the fungus corresponding to the root stem and leaves 

 of other plants — the mycelium — consists of very slender thread-like 

 tubes which may grow singly, or may form intricate masses, the 

 threads being more or less grown together. As compared with the 

 fruiting portion, the mycelium is very small and insignificant in 

 appearance. This may readily be seen by comparing the edible 

 part of the ordinary mushroom with the mold-like "spawn." The 

 part which we eat is really the fruit-bearing part of the fungus, and 

 the spores whicli take the place of the seeds of tbe flowering plants 

 are borne on the gills under the cap. These spores which are 

 exceedingly small and are seen as a black dust when fully mature. 

 The same relation between fruit and mycelium holds with most of 

 the fungi with which we are concerned. 



I have said that a fungus must live on organic matter, either 

 living or dead. Fungi are thus readily divided into two distinct 

 classes : Parasites^ those obtaining their nourishment from living 

 plants or animals; and saprophytes which feel wholly on dead 

 tissue. It should be added, however, that some fungi belong to 



