THE VARIOUS FORMS OF PLANTS 



151 



the bread to sugar and the proteid to a soluble form which will 

 pass by osmosis into the hyphse. Thus the plant is enabled to 

 absorb the material. This food is then used to supply energy and 

 make protoplasm. This seems to be the usual method by which 

 saprophytes assimilate the materials on which they live. 



Other Saprophytic Fungi. — The mushroom resembles a tiny umbrella. 

 The upper part is known to botanists as the cap ; the cap is held up by a 

 stalk or stipe. The under surface of the cap discloses a number of struc- 

 tures which radiate out from 

 the central stipe to the edge of 

 the cap. These are the gills. 

 If you place the cap of a mush- 

 room gills downward on the 

 surface of a piece of white 

 paper, being careful not to dis- 

 turb for at least twelve hours, 

 it win be found that when the 

 cap is removed a print of the 

 shape and size of the gills re- 

 mains on the paper. This is a 

 spore print. It has been caused 

 by the spores of the plant, which 

 have fallen from the place where 

 they were formed between the 

 gills to the siirface of the paper. 



Mycelium. — The mushroom 

 is, then, the spore-bearing part 

 of the plant. Where is the plant 

 body? This question is an- 

 swered if we dig up a little of 

 the earth surrounding a mush- 

 room. In the rich black soil is 

 seen a mass of little whitish 



threads. These threads form the mycelium of the fungus. The hyphes 

 of this part of the plant body take food from the organic matter in the 

 soil and digest it in the same maimer as did the hyphse of black mold. 

 The mushroom is a saprophyte. No sexual stage has yet been discovered. 



Food Value of Mushrooms. — The food value of the edible mushroom 

 has been much overestimated. Recent experiments seem to show that, 

 although they have a slight food value, they are far from taking the plaee 

 of nitrogenous foods, as was formerly believed by scientists. 



Other Fungi. — Many oth<T plants, both useful and harmful to man, 

 belong in this group ; among them are the yeasts, the various parasitic 



Mushrooms ; the j-ounger specimen, at the 

 right, shows the mycehum. Photographed 

 by Overton. 



