INTRODUCTORY 



scopic in size and variable in form and function, dependent on 

 their location in the plant and the functions which they perform. 



These cells are grouped into a tissue which must be studied 

 with the microscope and these tissues make up the organs, auch 

 as stems, roots and leaves. Having gained a thorough knowl- 

 edge of the character and arrangement of these tissues, it be- 

 comes possible to make an intelligent study of their functions 

 and the conditions which influence and control plant growth. 

 This may be followed by a study of the classification of plants 

 and the utilization of plant products. 



The groups in the plant kingdom from lowest to highest may 

 be represented as follows : 



Algae — ^Chlorophyll-bearing (i.e. green) plants 

 of simple structure and with simple 

 methods of reproduction. They range 

 from minute forms which cannot be 

 seen without a microscope to very large 

 Thallophytes forms. They are mostly aquatic. (See 



page 260.) 

 Fungi — Non-chlorophyll-b earing plants of 

 simple structure and methods of repro- 

 duction very similar to th« algae. (See 

 page 273.) 

 Liverworts — Plants which are more complex than 

 the Thallophytes but far more simple 

 than the higher plants. The reproductive 

 structures are much more complex than 

 in the Thallophytes. (See page 289.) 

 Mosses — Plants which are similar to the liver- 

 worts but of a more complex structure. 

 (See page 292.) 

 Ferns and The membere of this group have! a 

 related plants — structure which in many respects is 

 comparable to the higher plants, but the 

 methods of reproduction are very sim- 

 ilar to the Bryophytes. (See page 297.) 

 Gymnosperms — Seed-bearing plants usually known as 

 conifers or cone-bearing plants. They 

 are mostly evergreens. (See page 303.) 

 Angiosperms — Flower- and seed-bearing plants. Mostly 

 deciduous. (See page 312.) 



Bryophytes 



Pteridophytes 



Spermatophytes 

 (higher plants) . 



