88 



Minnesota Plant Life. 



pillar fungus, the black knot and all the other sac-fungi, arise 

 as a necessary consequence of some fusion of cells, equivalent 

 to that which took place in the black moulds. In the stalk- 

 fungi, to which group the mushrooms, puff-balls, club-fungi and 

 all their relatives belong, it is not so certain that a breeding-act 

 is always the necessary precursor of the fruit-body, but there is 

 much good evidence in 

 favor of such a supposi- 

 tion. 



All of the fungi which 

 have been considered up 

 to this point may be re- 

 garded as derived from 

 certain of the lower algse, 

 while the bacteria yet 

 to be discussed are very 

 closely related to the 

 blue-green algae. The al- 

 gal fungi seem, for the 

 most part, to be connect- 

 ed with the pond-scums, 

 leading over to such 

 forms as the black mould, 

 or with the green felts, 

 leading over to mildews 

 and fish-moulds. It is 

 reasonable to suppose 

 that all of the higher 

 fungi which have thus far 

 been passed in review are 

 derived, by a continuous 

 series of improvements, 

 from the algal fungi. 



Root-fungi. There are a few rather remarkable types of 

 fungi which should be treated separately. One of these is not 

 commonly known to make fruits of any sort, and, since botan- 

 ists depend upon fruit-bodies as the basis of their classification, 

 it is difficult to say where these fungi about to be considered 

 should be placed in the general system. They will be found 



FIG. 34. Twig-fungus on currant canes. After 

 Durand. Bull. 125, Cornell Expt. Station. 



