218 



PRACTICAL COURSE IN BOTANY 



......st 



insect visitors by its conspicuous appearance ? What is the 

 use of the projecting underlip? Is it any convenience to a 

 bee, for instance, to have a platform to rest on while gather- 

 ing pollen or honey? What is the use of the arched upper 

 lip? Cut it away and notice the exposed condition of the 

 stamens and pistil. Turn a flower upside down; what 

 would be the effect on a visiting bee or butterfly? (Exps. 

 83, 84.) 



244. Morphology of the flower. We have seen that the 

 venation of petals and sepals corresponds in a general way 

 with that of foliage leaves of the class to 

 which they belong, and that their arrange- 

 ment around their axis is analogous to the 

 arrangement of foliage leaves on the branch. 



In our study of 



inflorescence, i t 



was observed that 



flowers and flower 



buds occur in the 



same positions 



where leaf buds 



occur, and that 



they are subject 



to the same laws 



of arrangement 



and growth. We 

 learned, also, in our study of leaves, some- (f c M * 



7 ... showing transition 



thing about the wonderful modifications that from scales to 

 these organs are capable of undergoing ; and pet 

 finally, an examination of a number of different flowers has 

 shown them capable of undergoing modifications to an equal 

 or even greater extent, and examples of the transition of 

 almost any floral organ into another may be observed by one 

 who will take the trouble to look for it. Stamens and petals 

 are found in all stages of transformation, from the slightly 

 flattened filament of the star-of-Bethlehem, or the yellow 



FIG. 327. Staminodia, trans- 

 formed stamens of canna stimu- 

 lating petals : pet, petals ; st, 

 staminodia. 



FIG. 32 

 Flower of a cactus 



