142 



BOTANY. 



Germination then takes place, in some species by the pro- 

 duction of a tube, in others by the division of the proto- 



Fio. 70.— Resting spores of White Rust of Peppeigrass; at 4, still surrounded 

 by oBgone. B, C, formation of zoospores; D, free zoBspores. Magnified 400 

 times. 



plasm into zoospores (Fig. 70, B, G, B) whose subsequent 

 development is like that described above in case of the 

 conidia. 



Pi'acUcal Studies. — {a) Collect a quantity of Green Felt and pre- 

 serve it in a dish of water. After a few hours a large number of zoo- 

 spores may be observed collected at the edge of the water nearest to 

 the light. 



(i) Examine carefully mounted specimens of the bright-green fila- 

 ments, and look for the thickened lateral branches which produce 

 the zoSspores. 



(c) Select some of the oldest, yellowish filaments. Mount and ex- 

 amine with a low power for the sexual organs. In collecting speci- 

 mens for the study of the sexual organs it is necessary always to 

 take those masses which are yellowish and appear to be dying or 

 dead. 



(fi) Throw a dead fish into a pool of water in the summer, and ex- 

 amine it after a few days, when it will probably be found covered 

 with a mould-like growth. Remove a few filaments and look for 

 the formation of zoospores. The same Water mould (Saprolegnia 

 ferax) may often be found upon the bodies of young fishes, especially 

 in fish-hatching houses. 



(e) Examine the cells of Pond-scums, Desmids, Diatoms, etc., 



