206 LUSSOJfS WITH PLANTS 



235a. It. is commonly taught that the parts of flowers are modi- 

 fied leaves. This idea seems to have originated with the poet Goethe 

 (."Metamorphoses of Plants," 1790), who supposed that all the struc- 

 tures or members of flowers may have been derived from the leaf. 

 It has recently been suggested, however, that the evolution may 

 have been in the reverse direction, — that leaves may have been de- 

 rived from floral members. It is not necessary to accept either 

 hypothesis, for both foliar leaves and floral members may have arisen 

 independently from a common structure, as from stems; nor is it 

 necessary to assume that all leaves or all flowers have arisen in 

 the same sequence. The important lesson for the beginner is the 

 fact that floral members and leaves are essentially alike in origin 

 and that, upon occasion, one may pass into the other. 



Suggestions.— In illustration of all these remarks the pupil should 

 examine the double flowers of the gardens. Every one of these 

 flowers has a story to tell of transformation or evolution; and every 

 one is a witness that plants may be most profoundly modified by 

 any treatment or condition which is strange to them. In particular, 

 we may suggest a study of the common geraniums, carnations, roses, 

 fuchsias, petunias, balsams, datura or brugmansia, violets, and tulips 

 and hyacinths. The double aquilegias (or columbines) are very inter- 

 esting; also the double larkspurs. 



XXXVIII. PARTICULAR TYPES OF FLOWERS 



236. The one thing which must have been most 

 strongly impressed upon the pupil in these obser- 

 vations upon the flower is the fact of the great 

 and wide variation in forms. We have already 

 found many obscure or disguised parts. There are 

 still other disguises, which will be sure to puzzle 

 the pupil, to a very few of which we may give atten- 



