220 



GENERAL MORPHOLOGY OF PLANTS 



cells, each of which forms a zoospore capable of producing 

 the Coleoch&te plant again. 



^^s ,r^Cr 



Fig. 184. Fig. 185. 



Two sporocarps still Sporocarp ruptured by 

 surrounded by thallus. growth of egg to form ceil 

 Thallus finally decays and mass. Cells of this sporo- 

 sets sporocarp free. phyte forming zoospores. 



' Figs. 184, 185. C. scutata. , 



SIPHON GREEN ALG^ (SIPHONED). 



367. 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 

 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 

 of small motile gametes, or by the special organs, the sperm and 

 egg cases (antheridia and oogonia). 



368. The green felts (Vaucheria). The " green felts " are 

 good examples of the siphon algae. They occur in fresh-water 



Fig. 186. 

 Vaucheria sessilis, one antheridium between two oogonia. 



