Algae, Fungi, and Lichens. 273 



in the conjugating cell of one filament passes through the 

 tubular connection and fuses with the protoplast in the 

 conjugating cell of the other filament, all of the conjugat- 

 ing cells of one filament being receptive, and of the other 

 contributive. The two fused protoplasts organize a wall 

 about themselves, and become a resting spore which is 

 able to endure desiccation and other adverse conditions. 

 After a period of rest the spore germinates and produces 

 a filamentous individual similar to those from which it 

 sprang (Fig. 137). The filament which bears the spores 

 may be considered the female and the other the male, but 

 there is no structural differentiation into egg and sperm. 



166. Vaucheria. Vaucheria is a filamentous Alga of 

 another character. It grows either in water or on moist 

 and shady banks. Each individual is a tubular branched 

 filament which in its vegetative state is not divided by cell 

 walls. One end of the filament is modified in such a way 

 as to serve as an anchor to the substratum (Fig. 138). The 

 protoplast which lines the tubular filament contains many 

 nuclei and probably consists of many fused protoplasts. 

 Small rounded chloroplasts are found in great numbers in 

 the filaments. The wall is of cellulose without much 

 waterproofing, and the plant cannot flourish away from 

 water or moist places. The branched filaments have the 

 habit of interweaving, and so furnish each other mutual 

 support. 



167. Reproduction of Vaucheria. Vaucheria reproduces 

 by both the sexual and asexual methods. In the latter 

 process the protoplasm accumulates in a swollen end of 

 the filament, which becomes demarked from the rest of the 

 filament by means of a transverse wall. The swollen end 

 breaks open and the mass of protoplasm passes out and 

 swims about for a time by means of numerous cilia that 



