THE LIVING SUBSTANCE I >!•' PLANTS 



life of the cell ;i substance termed protoplasm. This substance 

 resembles somewhat the white of an egg, being viscid and rather 

 tenacious. The protoplasm is not of uniform consistency. The 

 r portion of it is finelj granular and is called the cytoplasm 

 while a denser rounded part is termed the nucleus. < >ther bodies, 



plastids, also denser than the cytoplasm are of common occurrence. 

 Such plastids as contain a green pigment, chlorophyll, are called 

 choroplastids or chloroplasts, and these produce the green color 



- {. M i 



ch A 



In. 2. Structure of the cell: ./. cell of ditch moss, Philotria; n, nucleus, 

 .-•. vacuole, ch, chloroplast. B, cell of carrot; ch, chromoplasts, n, nucleus. 

 ('. chromoplasts from rose hip. D, cells of Begonia; s, starch graii 

 :in. / . leucoplast, /. of potato forming a starch grain. 



of the vegetation i Fig. 2, A). Still other plastids, the chromo- 

 plasts, contain red or yellow pigments thai give the color to many 

 fruits and flowers, as the tomato, rose hip, squash, nasturtium 

 etc. (Fig. 2, /'. (1. Colorless plastids, leucoplasts, often occur 

 in cells hidden from the light. One group of these leucoplasts 

 forms the starch that appears in underground storage organs a« 



