J 56 LESSON'S WITB PLANTS 



ordinary stem, and if it is sometimes a matter of 

 definition to determine what are bracts and what 

 are floral envelopes, we begin to wonder if flowers 

 are so very much different from other parts of 

 the plant, after all. The lesson to be derived from 

 this discussion is not what particular interpreta- 

 tion has been placed upon certain facts, but that 

 there is endless variety, and that every fact and 

 phenomenon must be investigated for itself ; and 

 there is sometimes a gradation from leaves to flowers. 



Suggestions. — Involucres and bracts may answer the purpose of 

 petals. It would interest the student to find colored leaves upon 

 flower stems. Let him ask a florist for a plant of the scarlet 

 sage or the poinsettia; or he may grow the solarea, seeds of which 

 can he obtained of seedsmen. The wild flowers known as 

 painted-cup (castilleia) have very conspicuous, colored bracts or 

 leaves. The pupil will now be interested in tracing resemblances 

 between leaves and the parts of the perianth. 



XXIX. DICLINOUS FLOWERS 



176. We have seen that many flowers have not 

 both stamens and pistils. The willow is such a 

 case (Figs. 136, 137). The willow is also peculiar 

 in the fact that the flowers are borne in a dense 

 elongated scaly cluster. Such clusters of flowers 

 are called aments or catkins. 



176a. It is customary to speak of staminate and pistillate plants as 

 two sexes ; but sex in plants may not be comparable with sex in animals. 



