1908] 



HARVEY— PRAIRIE-GRASS FORMATION 



i°5 



some 7-5 dm high, and each of the branches is terminated by a very 

 striking head; yellow drooping rays, 6 to 9 in number and frequently 

 3 cm long, surround a deep-brownish columnar head some 4 cm high. 

 The prairie cone-flower occurs copiously upon lower and middle 

 slopes, extending crestward (fig. 1). In the former locations it fre- 

 quently assumes almost facial rank and gives a bright-yellow tone to 

 the entire floral aspect. It is a prolific and continuous bloomer, 

 dominating the aspect through the month of July and the greater part 



Fig. 1. — Late estival aspect; Ratibida colnmnaris upon a middle slope; the 

 ruderal Hotdeum jubatum in right foreground. 



of August, and extending up to the middle of September. Ratibida 

 is a perennial from a thick root. The achenes are provided with a 

 diminutive pappus of one or two teeth, and so lack of mobility and 

 great fertility result in its copious abundance in restricted localities. 

 It should be recorded that a few specimens with reddish-brown 

 rays having yellow tips and bases have been noted. 



At about the time Ratibida is spreading its neutral ray-flowers the 

 earlier flowers of Symphoricarpus appear, reaching their maximum 

 flowering two or three weeks later. The wolfberrv is of restricted 



