52 



PRACTICAL BOTANY. 



sometimes tinged with red. In the later stages of their 

 growth rounded masses appear in the protoplasm, each of 

 which develops a cell wall and becomes a resting spore. 

 Toadstool-like elevations also appear which bear resting 

 spores. The resting spores live after the moisture has 

 evaporated, and in the form of a dry powder are scattered 

 abroad by the wind until they strike some moist surface 

 where the conditions are favorable for their development, 

 when each spore is capable of growing into a new organism. 



In the beginning of this 

 growth, the spore de- 

 velops into a motile 

 Amcebalike form. These 

 forms meet and flow to- 

 gether, forming the so- 

 il^ // ^fpl^i called plasmodia, which 

 fflgik^ 2&&#m i* 1 some cases attain a 



considerable size. As 

 the. plasmodia increase 

 in size, a true flowing 

 movement takes the 

 place of the amoeboid 

 movements which char- 

 acterized the earliest 

 motile forms. In some 

 of the Slime Fungi, ciliated swarm spores form. These 

 move by a combined hopping, rotating, and creeping 

 motion, as well as by amoeboid movements. After a time 

 the cilia are lost, and the forms which now become 

 Amcebalike unite to form plasmodia. The earlier forms 

 of the Slime Fungi also multiply by repeated divisions 

 of the mass. There is no alternation of generations 

 from sporophyte to gametophyte ; the plant is the sporo- 

 phyte. There are, then, five distinct stages in the ex- 

 istence of these organisms, as follows : a. The spore, 



FIG. 25. Physarum album. (From Sachs, 

 after Cienkowski.) 1, spore ; 2, emis- 

 sion of its contents ; 3, the free contents ; 

 4, 5, the same as swarm spore with one 

 flagellum ; 6, 7, the same after losing 

 their flagella; 8, 9, 10, 11, fusion of 

 amoeboid forms ; 12, a small plasmod- 

 ium. 



