Minnesota Plant Life. 



57 



In these forms, however, and in many of those to follow, the 

 conspicuous part of the plant is really nothing more than its 

 highly developed fruit-body, while the vegetative portion con- 

 sisting of a spongy or cottony substance lies imbedded in the 

 decaying timber. 



Shelf-fungi. Related to the prickle-fungi are the well-known 

 pore-fungi, or shelf-fungi, which are such familiar objects in the 

 woods of Minnesota. Often they seem to be growing upon liv- 

 ing trees, but it will be found upon examination that they have 



FIG. 16. Shelf-fungus growing on dead stump of oak tree. After photograph by Hibbard. 



attacked some wounded or dead portion of the trunk, for these 

 fungi are none of them truly parasitic. They are more com- 

 mon, indeed, upon dead timber, either prostrate or standing. 

 Very pretty examples of shelf-fungi are abundant upon the 

 birch-trees of Minnesota, and this particular species is known 

 as the birch-tree pore-fungus. The fruit-bodies hang down 

 somewhat like bells, are of a white color, not \voody but with 

 much the consistency of. punk or cork. They grow larger from 

 year to year, the new growth covering that of former summers, 

 and every season a new layer of pores is produced upon the 



