466 



THE UMBELLALES 



usually white or yellow and grouped into flat-topped inflores- 

 cences (umbels), which are usually surrounded by bracts, called 

 the involucre (Fig. 324, .-1, B). These features are well seen in 

 the wild carrot which has become a troublesome weed in pasture 

 lands and meadows. The calyx lobes are very small, a feature 

 likely to be seen in any epigynous flower. The incurved petals 

 alternate with the five stamens and in the center of the flower, the 



' 



FIG. 324. A common form of the Umbellales: .4, stems of wild carrot 

 (Daucus) with flowers arranged in compound umbels. B, inflorescence with 

 all the umbels removed but one in, bracts of the involucre. C, forms of 

 flowers, the one on the right being a flower from the margin of the umbel. 

 The corolla is enlarged and irregular, thus adding to the conspicuousness 

 of the inflorescence. D, corolla partially removed to show the epigynous 

 character of the flower and the cushion-like nectary at the base of the styles; 

 o, ovary. E, fruit splitting into two nutlets. F, portion of hollow stem 

 with sheathing of leaf base. 



two styles broaden out into a conspicuous nectary above the 

 ovaries. The fruit is a schizocarp, splitting into two nut-like 

 parts after the manner of the maple (Fig. 324, ). The flowers 



