l 5° BOTANICAL GAZETTE. [June r 



to 4 lines long) narrowed each way from above the middle, 

 the base being narrower than the truncate apex, often stronger 

 ribbed on the outer face, giving a triangular shape, quite 

 glabrous ; no awn or pappus of any kind. (Fig. 22.) 



Specimens of this species are very rare in collections. 

 The only fruiting specimen found, and from which the 

 drawing was made, was collected by Dr. Gray in 1843. Good 

 specimens are very much desired by the Department of Ag- 

 riculture. 



C. aurea Ait. in its typical form is easily distinguished by 

 its fruit characters, but in some of its varieties approaches 

 the next. Achenia short (1 to 2 lines long), broadly cuneate, 

 slightly pubescent ; awns two short broad teeth or wanting. 

 (Fig. 23.) * 



Drawing from Curtiss' Georgia collection of 1875. 



in } n t 6 Var * subinte g ra > as shown by Chapman's plant 

 (Columbia Coll. Herb.), the awns are longer, acute and 



spreading and resemble some forms of C. trichosperma. 

 (Fig. 24.) 



C. trichosferma Michx. is rather well marked in its fruit 

 characters, although it presents various forms, some ap- 

 proaching C. anstosa on the one hand and C. aurea on the 

 other. Achenia 2 to 4 lines long, a line or less broad, slightly 

 pubescent or glabrous, ovate-oblong to cuneate-oblong ; awns 

 broad at base, terminating in a short acumination, erect or 

 turned inward. (Figs. 25 and 26.) 



Short's plant from Kentucky and Hall's from Kansas 

 have narrow achenia, approaching certain forms of the next. 



*** Achenia very flat, wingless but with thin margins. 



C. aristosa Michx. is not easily denned as it grades almost 

 insensibly into several related species on the one hand and 

 crosses so commonly with various species of Bidens on the 

 ottier. It seems almost impossible to draw any specific or 

 generic lines about it. Achenia very flat, sometimes slightly 

 ribbed on the faces, 3 lines long, oblong to obovate ; awns 

 generally quite long, sometimes equalling the achenium and 

 spreading, but m the var. mutica obsolete or nearly so. 

 (Figs. 27 and 28.) J 



Fig. 31 is from J. Q. A. Fitchev's plant, collected in 

 1 l^fr Louis, Mo " and considered by Dr. Gray as a 

 hybrid from this species and Bidens chrysanthemoides. Fig. 

 32 is from a plant collected in 1873 by Dr. F. Brendel of 



