246 



GENERAL MORPHOLOGY OF PLANTS 



rounded by an envelope of branches growing from cells adjacent 

 to the egg case, and then passes through a resting stage. When 

 it germinates it produces a small mass of cells, each of which 

 forms a zoospore capable of producing the Coleochcete plant 

 again. 



X^s ^?^^' 



Fig. 193- 



Two sporocarps still sur- 

 rounded by thallus. Thallus 

 finally decays and sets sporo- 

 carp free. 



Fig. 194. 



Sporocarp ruptured by 

 growth of egg to form cell 

 mass. Cells of this sporo- 

 phyte forming zobspores. 



Figs. 193, 194. C. scutata. (After Pringsheim.) 



SIPHON GREEN ALG^ (SIPHONED). 



380. General characters. The siphon algae are mostly 



filamentous and branched, but are characterized by the absence 



of cross walls in the vegetative threads, or by few such walls. 



The threads are thus like a siphon or tube. There are many 



Fii?. 195. 

 Vaucheria sessilis, one antheridium between two oogonia. 



nuclei in the protoplasm of a single thread or compartment. The 

 chlorophyll bodies are numerous, small, oval, flattened bodies. 

 Asexual reproduction is by zoospores, or in some cases by non- 

 motile spores. Sexual reproduction is either by the conjugation 



