150 PLANT BIOLOGY 



consist of a mass of fine interlacing threads called the mycelium. 

 (See Fig. 75.) Single threads are known as hyphce. 



160. Reproduction and life history of bread mold. Some of 

 the hyphse in their growth assume an upright position, and each of 

 these at the upper end develops a little globular white mass or spore 

 case. (See Fig. 75.) An examination with the high power of the 

 microscope shows that the spore cases are filled with tiny cells 

 known as spores. When the spores are ripe, the spore cases appear 

 brown or black, they break open, and the spores are scattered. 

 If these spores fall on food of some kind, such as bread, they begin 

 to germinate, and each one produces another mass of threads with 

 spore cases on erect hyphaB. In other words, the mold produces 

 spores and the spores reproduce the mold. The spores of molds 

 are in the air nearly everywhere, hence we see why molds appear 

 so quickly on foods of various kinds, provided they are moist and in 

 a warm place. 



161. Nutrition in the fungi. Molds, like other fungi, as we 

 have already said, cannot manufacture their own food out of the 

 materials obtained from the soil and air, but are dependent on foods 

 made by green plants. Certain of the threads called the nutritive 

 hyphce form ferments which digest the food compounds found in 

 bread or other substances on which the mold is growing, and then the 

 digested food is absorbed, used in growth, and in the production of 

 energy. Other threads develop the spore cases and so are called re- 

 productive hyphce. Hence, it is evident that fungi, like all plants, carry 

 on both nutritive and reproductive functions, but on account of the 

 lack of chlorophyll are, like animals, dependent on the green plants 

 for their supply of food. 



162. Suggestions for laboratory work on bread mold. No. 



63. Sow bread mold as suggested in 159 in sufficient quantity 

 to supply each two pupils with a piece of the moldy bread. Pupils 

 should examine a specimen with a hand magnifier, describe the 

 appearance of the mycelium and hyphae bearing spores, and 

 should then make a drawing to show these points. Some of the 



