102 



A TEXTBOOK OP BOTANY [Ch. Ill, 13 



(Fig. 62 a), having very characteristic forms and markings, 

 cUffering with the kind of plant (Fig. 63). Starch is 

 formed from sugar only in the plastids of the cells, either the 

 chloroplastids of the green cells, or the colorless leucoplastids 



Fig. 03. — TjToical grains of various starches ; liighly magnified. Upper 

 row. Potato, Maranta, Pea, Hyacintli ; middle rou\ Wlieat, Oats, Sago, 

 Smilax ; lower row, Canna, Corn, Bean, Oxali.s. 



Tlie ctiaracteristic forms and marltings of the grains form invaluable 

 identification marks in the recognition of adulterations of foods, etc. (Re- 

 drawn from Ganong, The Living Plant.) 



of storage cells ; and it cannot as yet be made artificially. 

 Starch is particularly abundant in tubers (Potato), tuberous 

 roots (Sweet Potato), bulbs (Lilies and Hyacinths), and es- 

 pecially in large .seeds, to all of which its presence imparts a 

 dull, white, firm aspect, in marked contrast to the soft trans- 



