e2.G THE STRUCTURE OF ECONOMIC PLANTS 



ligulate corolla, and the pappus so that the flower is epigynous. 

 (Fig. 3^6, £, F.) 



The mature pappus is white, fine, and soft, and ultimately 

 functions in the dissemination of the fruit. (Fig. 315, D, f.) 

 The sympetalous ligulate corolla is yellow or whitish yellow, and 

 the truncate, five-toothed ray consists of five undi verged petals. 

 Each ray inclines obliquely outward so that the expanded head is 

 about a centimeter and a half in diameter. (Fig. 3x5, C, D.) The 



da, 



Tpap 



Fig. 3x6. Floral development : A, head, showing flower primordia at time of development 

 of corolla; B, same, showing development of corolla, stamens, and pappus; C, D, and E, 

 successive stages in development of individual flower ; F, longisection through flower showing 

 early and later stages in development; ^«, anther; wr, carpel ; c/^, corolla ; w, ovule; ovy, 

 ovarian cavity ; pap, pappus ; p m c, pollen mother cells ; sta, stamens. (After Jones, Hil- 

 gardia.^ 



filaments of the five stamens are diverged from the base of the 

 corolla tube as separate structures, but the anthers are united, 

 forming a cylinder which projects beyond the corolla tube and 

 surrounds the style. The ovary is unilocular and the slender 

 style is unbranched up to its point of emergence from the anther 

 cylinder where the two stylar branches terminate in a two-lobed 

 stigma. (Fig. 3x5, D, £.) The head is surrounded by a cylindri- 

 cal involucre consisting of a series of bracts that are closely im- 

 bricated in the bud, the outermost bracts being shorter than the 

 inner ones. (Fig. 3x5, B.) 



