310 NATURE-STUDY 



The onion and lily bulbs are also modified stems. Cut 

 an onion through lengthwise, and note the thickened leaves 

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

 condensed leafy bud. The scales on the outside serve for 

 protection, those within to store nourishment. Examine 

 also tulip and amaryllis bulbs. Raise some hyacinth bulbs 

 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 mainly of water and starch. Show with the iodine 

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

 Examine some starch grains under a microscope. This 

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





