188 



Elementary Biology. 



The flower. It has already been pointed out that the 

 flower of the buttercup conforms to what is known as the 



FIG. ^.-VERTICAL .SECTION OK RANUNCULUS. PentamerOUS type, 

 (Maout and Decai^ne.) that is tO Say, has itS 



parts arranged in 

 whorls of five each. 

 This may be best 

 seen by comparing 

 the floral diagram 

 (fig. 103) with the 

 vertical section of the 

 flower (fig. 102). The 

 sporophylla are more numerous than in the lily, and are 

 spoken of as indefinite. The stamens conform to the type 

 already described for the lily. The carpels are, however, 

 in Ranunculus free as well as numerous. Moreover, each 

 carpel contains only one anatropal sporangium (ovule). 

 After the ovum in its interior has been fertilised the carpel 

 is then a one-celled one-seeded fruit. The carpels in the 



lily formed a three- 

 celled many-seeded 

 fruit. All the sporo- 

 phylla, as well as the 

 perianth leaves, spring 

 from a convex thalamus 

 or floral axis, and the 

 stamens rise free from 

 each other and the peri- 

 anth, and at a lower 

 level than the carpels. 

 The stamens (andrce- 

 cium) are therefore said 

 to be hypogynous, or 

 beneath the carpels 

 (gyno3cium). The ac- 

 count of the structure of the sporophylla and the essential 



FIG. 103. FLORAL DIAGRAM OF RANUN- 

 CULUS. (Allen.) 



a a, carpels ; b b. stamens ; cc, petals ; 

 dd, sepals. 



