I J 



FIG. S. Cnicus arvensis. Floral development: A, receptacle almost evenly convex; 

 appearance of papillae to become flowers ; <?, a single papilla more advanced, show- 

 ing beginning of corolla ; /), corolla more prominent ; E, stamens distinguishable ; 

 F, carpels and pappus (calyx) evident; G, carpels beginning to form cavity of 

 ovary ; H. ovule readily distinguishable ; /, ovule showing megaspore mother-cell 

 and single thick integument : 5, bract of involucre ; c, corolla ; *, stamen ; 0, carpel ; 

 p. pappus (calyx). A-H x 50 ; I x 100. 



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