DICOTYLEDONOUS PLANTS 165 



flowers, bracts of the involucre in one series, united at the 

 base and generally longer than the flowers. Akenes with long 

 beaks and plentiful brownish pappus hairs, that are feathery, 

 with naked tips, and so numerous that they interlace. 



T. porrifolius L. This is common, having escaped from culti- 

 vation. The large purple heads are on thick, hollow stems. The 

 flowers soon fade. 



IV. MICRO'SERIS 



Low herbs, with leaves chiefly radical and heads of yel- 

 low flowers on naked stems, mostly nodding before opening. 

 Akenes ribbed, truncate at apex ; pappus of several papery 

 scales that spread in fruit. The species are rather difficult to 

 distinguish. 



V. STEPHANOME'RIA 



Herbs with smooth, almost leafless branches. Heads of pink 

 flowers, numerous, sessile, scattered along the naked stems, 

 in bloom only in the morning. Akenes 5-ribbed, truncate at 

 both ends, with plumose bristles. 



S. virga'ta Benth. This is simple or widely branched, and often 

 grows to a height of several feet. The bracts of the involucre are 

 in a single row, with a few loose ones at base. This is in bloom 

 through the summer and fall. Widely distributed. 



VI. RAFINES'QUIA 



Annual, smooth herbs, with leafy, branching stems, and 

 heads of white or flesh-colored flowers an inch in diameter, 

 terminating the branches. Akenes terete, gradually nar- 

 rowed to a slender beak. Pappus ivhite, cobwebby. 



R. Califor'nica Nutt. This is the common species, which is widely 

 distributed but seldom abundant. 



VII. MALACOTHRIX 



Generally annual, with leafy or scape-like stems. Flowers 

 various. The akenes have the apex developed into a crown, and 

 the silky pappus bristles falling in a ring. 



