The Saprophytic Fungi of Eastern Iowa. 31 



enable the student to identify our nativ-^e species. In this way 

 it is hoped not only to increase the public interest in the sub- 

 ject in hand, but also to make some contribution to the more 

 perfect knowledge of our indigenous flora. 



Fungi are flovverless plants, whose most obvious character- 

 istic is the absence of green color, or as the botanist would 

 say, of chlo?-ophyI, the green coloring matter of leaves 

 and herbaceous plants generally. In consequence of this 

 lack, fungi are in large measure dependent for their 

 food upon matter organized by other plants or by animals, and 

 cannot or at least do not elaborate for themselves food out of 

 inorganic material. The organic matter upon which fungi 

 subsist may be either dead or living, hence we find these plants 

 everywhere where organic matter is present, on leaves and 

 stems, flowers and fruits, on plants of their own kind, on the 

 tissues of living animals as well as upon the detritus of all 

 these things dead and returning to their original elements. 

 Fungi which live upon living organisms are parasites — para- 

 sitic in habit — those that feed upon dead organisms are sap)'o- 

 phytes — saprophytic in habit. The same fungus may live in 

 both ways or in either way according to circumstances. 

 Thus the little green mould with which everybody is familiar, 

 usually saprophytic, may, on occasion, be parasitic, attacking 

 the sound tissues of an apple, for instance, where the skin is 

 broken. Usually however these plants are quite restricted 

 in their diet, and are either purely parasitic or purely sapro- 

 phytic. In the case of such as are parasitic the plant bearing 

 the fungus is known as the host. Ordinarily the parasite 

 affects always the same host, although sometimes more than 

 one species of green plant is called upon to furnish entertain- 

 ment for a given parasite, and sometimes the parasite is mi- 

 gratory, spends different phases of its life-history on different 

 widely unlike host-plants, as for instance the grain rust, to be 

 further discussed hereafter. A<rain there are certain funcfi 



