FLORAL SYMMETRY, ETC. 129 



color and delicacy of petals ? Have you not seen in 

 the same flower some sepals that were green, and 

 some changed more or less toward petals? or, the 

 same sepal green without and petal-like within ? Have 

 you not seen the involucre made up of colored bracts, 

 which gave it the aspect of a corolla ? Have you not 

 sometimes met with flowers in which you could see 

 the gradual transition from petals to stamens? or 

 flowers in which some of the stamens or carpels were 

 changed to green foliage-leaves? Have you ever 

 known of single flowers becoming double by cultiva- 

 tion, and of stamens and carpels replaced by petals ? 

 Did you ever happen to see a leafy shoot growing out 

 from the centre of a flower, or of a flower-bud ? All 

 these appearances are common enough ; and, if you 

 have not seen them, you may easily do so by keeping 

 your eyes about you. 



It is from these singular aspects of plants, joined 

 with the study of their development, that botanists 

 have come to regard flowers as altered branches, and 

 floral leaves as changed foliage-leaves. They speak 

 of carpels as carpellary leaves, stamens as staminal 

 leaves, petals as corolla-leaves, and the sepals as calyx, 

 leaves. 



If this be so, the laws of arrangement of floral 

 leaves ought to agree with the phyllotaxy of foliage- 

 leaves. Botanists say that it does so agree, and the 

 place where it is best seen is in the flower-bud. The 

 arrangement of floral leaves should also be studied, 

 because it is important in helping to determine the 

 affinities of plants. 



To observe this arrangement, make an horizontal 

 section of a bud just before it opens. Be careful to 



