LIFE HISTORIES OF FUNGI 259 
harmful result followed. The discoverers of the toxin 
suggest that the discovery may possibly throw light on 
"pellagra" and some of the destructive diseases of cattle, 
such as "cornstalk-disease," and the "horse-disease," 
prevalent in some of our western states, and for some 
time thought to be due to some food-impurity. 
262. Vegetative Multiplication. At various points the 
mycelium produces one or more upright, aerial hyphae, 
15 to 20 millimeters high, and of larger diameter than the 
mycelial hyphae. One or more of these hyphae eventu- 
ally bend over and grow for a short time along the 
surface of the substratum, like the stolons or "runners" 
of such plants as strawberries. Finally, at their free ends 
there develop slender hyphae that penetrate the sub- 
stratum, like rhizoids, and another group of the larger, 
aerial hyphae, one or more of which may repeat the process 
just described. The formation of these stolons suggested 
a former name of the plant, viz., Mucor stolonifer. 
253. Asexual Reproduction. At the tip of each up- 
right hypha there develops a globular sporangium, and 
hence the hypha is called a sporangiophore (Fig. 186). The 
protoplasm is constantly streaming up the sporangiophore, 
getting more and more dense toward the sporangium, and 
contains large numbers of nuclei. Further down, to- 
ward the base of the sporangiophore, the protoplasm 
becomes thinner and thinner, and the nuclei, fewer in 
number, finally disintegrate. In the meantime the tip 
of the sporangiophore increases in size until the globular 
sporangium is formed, rich in cytoplasm and nuclei. 
By degrees the protoplasm becomes more dense toward 
the periphery, and gradually thinner toward the central 
portion, where large numbers of vacuoles develop. Soon 
