LESSONS WITH PLANTS 



333 



the structure of in a general 

 perhaps the best for teaching 



3 recognize but understand 

 ^ay. 



The common sunflower is 

 he structure of com- 

 iosites. A few belated 

 pecimens may still be 

 Dund in the fall when 

 chool begins. But the 

 ingle garden zinnias, 

 nd single asters, the 

 did sunflowers, and the 

 aisies will do very well. 

 d first thought one 

 '■ould think that what 

 ; generally called a sun 

 flower" is really a sin- 

 le flower, but closer ex- 

 mination will reveal 

 le fact that this is an 

 ggregation of hundreds 

 f very small flowers 

 lassed together in a 

 at head. Note first the 

 reen calyx-hke leafy 

 :ales on the outside of 

 le whole. This is not a true calyx, but is called an in- 

 olucre. Note how the scales are in several overlapping 

 3WS. Next within the green involucre comes a circle of 

 at, ribbon or strap-shaped, colored parts that are often 

 Tongly called petals. They are not petals, but whole flow- 

 rs. Pull out some of these flowers. Note that the flat 



Fig. 132. Pussy-willows- 

 (The pussies are flower buds.) 



