THE GENERAL CHARACTERISTICS OF PLANTS 11 
mental units of which the plant body is formed, and carries out 
all of the life processes of the plant. 
The herbs, shrubs and trees discussed in the preceding 
paragraphs represent but few of the vast array of forms which 
Fic. 5.—Two Blue-green Alge. A, B, C, D, E, Gleocapsa; F, Oscillatoria showing 
a dead cell (¢d) which marks a place of separation into segments. (A), Gleocapsa, 
parent cell composed of central protoplast containing scattered chromatin granules, 
surrounded by cell wall and 3 mucilaginous envelopes; (B), parent cell is shown 
elongated, the protoplast in process of division to form two daughter protoplasts; 
(C), daughter protoplasts, each surrounded by two gelatinous envelopes and both 
within the original parent envelopes; (D) the daughter protoplasts shown in C 
have just divided to form granddaughter protoplasts which have later separated, 
each forming envelopes of its own but all four encircled by the parent envelope. 
make up the Plant Kingdom. Many additional kinds of plants 
varying in form, habitat and method of living will be discussed in 
the chapters to follow, but in order that the student may 
approach the study of these with better understanding, it seems 
