The Forms of Leaves. 



51 



Fig. 37. Scaly bulb of a 

 lily. 



ones which resemble grains 

 of rice.* (See Fig. 38.) 



EXERCISE 30. 



The Forms of Leaves. 



Leaves are very import- 



ant organs, since it is their 



office to change plant food 



( chiefly carbon-dioxide 



and water) into substances 



(chiefly starch) which after further changes 



are used to build 



up the plant. This 

 work is like that of the stomach 

 in animals. Leaves also do a 

 kind of work for the plant simi- 

 lar to that done by the lungs of 

 animals. 



Guided by Fig. 40 arrange 

 your leaves in three sets: (i) 



Fig. 



cated bulb of soap 

 root. 



Fig 



Bulb of Fritillaria lanceolata . 



* The development of rootstocks and bulbs should be studied by pupils when- 

 ever opportunity offers. They might find out what becomes of the old bulb and 

 how new ones are formed, whether a single scale of a bulb can be made to grow 

 or not, etc. Soap root has a very interesting bulb and should be obtained if 

 possible. Cut crosswise, its halves make very effective flesh brushes and at the 

 same time furnish a better cleansing material than soap. The outer coats of 

 many native alliums are interesting objects under a microscope. The rootstocks 

 of the European or field morning-glory, now a common pest in the coast valleys, 

 would be good material for an exercise. Pupils might tell what they know about 

 the habits of the plant and the methods used to extirpate it. The teacher might 

 try the iodine test for starch upon any of these storage stems. 



