Classification of Organisms 



THIS CLASSIFICATION often includes 

 the classes and sometimes also the orders. 

 The phyla within each kingdom, and the 

 classes within each phylum are arranged, so 

 far as possible, in order of increasing com- 

 plexity. 



The number of species given for each 

 phylum is the approximate number of living 

 species described and named. In many, prob- 

 ably most, phyla there are undoubtedly many 

 more species still undescribed. 



Kingdom PLANTAE 



Organisms usually having rigid cell walls; 

 nutrition autotrophic, saprophytic, or para- 

 sitic. The line between the plant and ani- 

 mal kingdoms is not at all sharp, as explained 

 in the text. 



I. Subkingdom THALLOPHYTA 



Primitive, mainly aquatic plants, with no 

 embryo stage in development and no highly 

 differentiated tissues. 



Phylum CYANOPHYTA: the blue-green al- 

 gae; no distinct nuclei or chloroplasts; prob- 

 ably the most primitive of existing plants. 

 (2300 species.) 



Phylum EUGLENOPHYTA: euglenoids; with 

 flexible cell walls; flagellated; sexual repro- 

 duction virtually absent; store paramyhim; 

 nuclei and chloroplasts well defined. (250 

 species.) 



Phylum CHLOROPHYTA: the green algae; 

 including desmids; unicellular, colonial, or 

 simple multicellular forms, with definite nu- 

 clei and chloroplasts. (6000 species.) 



Phylum CHRYSOPHYTA: the yellow-green 

 algae, the golden-brown algae, and the dia- 

 toms. (5000 species.) 



Phylum PYRROPHYTA: the cryptomonads 

 and dinoflagellates. (3000 species.) 



Phylum PHAEOPHYTA: the brown algae, 

 with multicellular, often large bodies— the 

 large seaweeds. (1000 species.) 



Phylum RHODOPHYTA: the red algae. Mul- 

 ticellular, usually marine plants, sometimes 

 impregnated with calcium carbonate. (3000 

 species.) 



Phylum SCHIZOMYCOPHYTA: the bacteria. 

 (3000 species.) 



Phylum MYXOMYCOPHYTA: the slime 

 molds. The body consists of a mass of proto- 

 plasm containing many nuclei, but not 

 sharply divided into cells. Movement by ame- 

 boid motion (2500? species.) 



Phylum eumycophytA: the true fungi. 

 (70,000 species.) 



Class Phycomycetes: the algal fungi— bread 

 molds and leaf molds. 



Class Ascomycetes: the sac fungi— yeasts, 

 mildews, and cheese molds. 



Class Basidiomycetes: mushrooms, toad- 

 stools, rusts, and smuts. 



Class Deuteromycetes: a heterogeneous col- 

 lection of fungi in which sexual reproduction 

 is unknown, and which are not easily as- 

 signed to one of the other classes. 



II. Subkingdom EMBRYOPHYTA 



Plants with an embryo stage in development; 

 generally less primitive; more or less adapted 

 to terrestrial conditions. 

 Phylum BRYOPHYTA: multicellular, usu- 



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