180 



THE PLANT WORLD 



Classification of plants. Four great divisions or phyla of the 

 plant kingdom are : the Thallophyta (tha-lof i-td), known as thallus 

 plants, which do not have roots, stem, or leaves ; the Bryophyta 



5PERKAT0PHYTA 

 produce I 

 seeds i 



PTER1D0PHYTA 



ferns 



ARTHR0P0DA CHORBATA 



crustaceans I man, 

 insects I mammals 



"K0LLU5CA 



clams 



ANNELIDA 



5egmentecCvorms< 



PJtATrKELMlNTrK 



flatvorms 



BRYOPHyTA 



mosses 



ECK1N0DERKATA 



Starfish- 



NEMATHELN1NTHE5 

 J roundworms 



COELENTERATA 



* hydra 



-pORIF£PA x 



PROTOZOA 



simple^ 

 animals- 



THALLOPHYTA 

 simple plants 



All plants and animals developed from a common ancestor and are 

 classified under the phyla given in the above diagram. 



(bii-of'i-td), which include the mosses; the Pteridophyta (ter'i- 

 dof'i-td), which include the ferns; and the Spermatophyta (spur'- 

 md-tof'i-td), which embrace the seed-producing plants. 



Practical Exercise 2. Of what use is a system of classification? Write a 

 brief paragraph on this subject. 



Self-Testing Exercise 



Plants and animals may be placed in groups based on (1] 



A group containing individuals which are (2) in (3) 



and which will (4) others of the same kind is called a 



(5). Species are placed in a (6) and more (7) group, 



which is called a (8) . These groups in turn are placed in 



still larger groups, called, as they grow more inclusive, (9), 



(10), (11), and (12). 



