Iff 



Cystolith in 



leaf of 

 rubber plant 



iiij 



'■111' 



Resin in duct 

 of pine 



Shedding 

 of bark 



PLANT WASTES 



.<^->^ 



Raphides in 

 root cell of 

 spiderwort 





Glandular Chromoplasts Calcium 

 hairs of in petal of oxalate in 

 geranium nasturtium linden phloem 



Latex tubes in 

 dandelion root 



Latex tubes of 

 rubber tree 



m 



Oil gland in 

 orange peel 



Fall of leaves 



Gum exuding from 

 injured cherry tree 



Crystals and other bodies found in plant cells or in specialized ducts and spaces 

 are often waste materials locked up out of the way of active living cells. Where such 

 materials are accumulated in leaves and bark of long-lived plants, or even in seeds, 

 they become removed from the plant protoplasm 



Storage and Stowage in Plants The masses of starch, fat and protein 

 accumulated in the cells of many plants are normally used by the plants 

 themselves — unless we or some other animals take them away first. But 

 because of their obvious share in the life of the plants, we speak of them as 

 "stored" foods. Yet the same plants and many others accumulate in their 

 tissues quantities of insoluble materials which they never use again. These 

 substances are in many cases injurious to living protoplasm, although hu- 

 man beings have found ways of using them for their purposes. Such mate- 



215 



