3IO NATURI'>STUDY 



The onion and lily bulbs arc also modified slcms. Cut 

 an onion througli lengthwise, and note the thickened leaves 

 that surround a kind of central bud, the whole forming a 

 condensed leaf}' bud. The scales on the outside serve for 

 jjrotection, those within to store nourishment. Examine 

 also tulip and amaryllis bulbs. Raise some hyacinth bulljs 

 in water. 



The potato is another sort of underground stem, a short 



Fig. 115. Rootstalk of Solomon's Seal, a Storehouse of Food. 



and rounded root-stalk. The eyes represent buds, each of 

 which is capable of sprouting and forming a new plant. Cut 

 a piece of potato containing only one eye, plant it, and raise 

 a plant. Set a potato in a glass or can of water and note 

 the shoots that arise from the eyes. The potato is com- 

 posed mainlv of water and starch. Show with the iodine 

 test that it has starcli. Show starcli made from potato. 

 Examine some starch grains under a microscope. This 

 starch was made by the leaves of the plant and stored away 



