Survey of Plant Kingdom 117 



(fu ko -zan' thin) (L. jucus, alga or seaweed; xanthos, yellow) . Usually 

 there are several plastids per cell^ but no pyrenoids are present. Each 

 cell has a single, organized nucleus and may contain vacuoles. Some of 

 the cells have an organization similar to that of higher plant cells, some 

 even having a centrosome similar to that of animal cells. Stored foods 

 are jats and soluble sugars. 



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Fig. 31. — Photograph of several species of diatoms of the phylum Chrysophyta. 

 (Copyright by General Biological Supply House, Inc., Chicago.) 



Brown algae possess alternation of generations or metagenesis (met a- 

 jen'esis) (Gr. meta, over; genesis, origin) in which a free-living, multi- 

 cellular, gamete-producing gametophyte (gam -me' to fite) (Gr. gamos, 

 marriage; phyta, plants) alternates with a free-living, multicellular, spore- 

 producing sporophyte (spor'ofite) (Gr. spora, spore or "seed"; phyta, 



