BIOLOGY OF HIGHER SEED PLANTS 69 



nodes and internodes ? Where do the flowers origi- 

 nate on the axis ? Is there any structure below the 

 flower stalk corresponding to a leaf ? To what part 

 of an ordinary leafy shoot would a flower on the 

 inflorescence axis correspond most nearly,- to a leaf 

 a bud, or a branch ? On what evidence do you base 

 your conclusions ? See Fig. 212 of the text. 

 b. The inflorescence and pollination. Are the open flowers 

 at the apex or at the base of the inflorescence ? Is 

 the inflorescence an advantageous arrangement for 

 securing cross-pollination, or the transfer of pollen 

 from the anther of one flower to the stigma of 

 another flower, by insects ? Compare an inflores- 

 cence with solitary flowers in this respect. Sketch 

 an inflorescence and a portion of the stern below it. 

 Name the parts correctly. 



STRUCTURE OF PAPILIONACEOUS FLOWERS 



STRUCTURE OF THE FLOWER 



Examine flowers of some member of the pea family and com- 

 pare their structure with that of a simple flower like that of 

 the mandrake. 



1. Perianth. How many whorls, or sets, of organs in the 



perianth ? Are the members of each whorl regular or 

 irregular in form ? How many parts in each whorl ? 

 Are the parts of each whorl united or separate ? Remove 

 the parts of the perianth and place them in their proper 

 order on the table. Sketch the parts of the corolla. 



2. Essential organs. How many stamens are there ? Are 



they separate or united?. How are the stamens related 

 to the pistil ? Study the form and external features of 

 the ovary, style, and stigma. Study the style and stigma 



