172 SYNGENESIA P. ^QUALIS. 



251. ASTER. Receptacle naked ; down simple ; calyx imbricated, 

 lowermost scales spreading ; florets of the radius more 

 than 10. 



250. SENECIO. Receptacle naked ; down simple : calyx double, 

 the innermost cylindrical, of numerous equal scales, outer 

 of several minute ones, scales all withered at the extre- 

 mity. 



249. TUSSILAGO. Receptacle naked ; down simple ; calyx simple, 

 tumid at the base, scales numerous, equal, somewhat 

 membranous ; seed obovate, compressed. 



257. ANTHEMIS. Receptacle chaffy ; seed crowned with a slight 



border ; calyx hemispherical, scales nearly equal ; florets 

 of the radius numerous, oblong. 



258. ACHILLEA. Receptacle chaffy ; down none ; calyx ovate, 



scales imbricated, unequal ; florets of the radius 5-10, 

 roundish, somewhat heart-shaped. 



III. POLYGAMIA FRUSTRANEA. 



259. CENTAUREA. Receptacle bristly ; down simple or feathery, 

 rarely wanting; florets of the radius funnel-shaped, dila- 

 ted, irregular, without stamens or style. 



I. POLYGAMIA ^EQUALIS. 



228. TRAGOPOGON. 



1. T. pratemis, smooth, milky ; leaves keeled, tapering, dila- 

 ted, and somewhat undulated at the base ; flower-stalk cylindri- 

 cal ; calyx about equal to the corolla. Yellow Goafs-beard. 

 Hal. Meadows and pastures, frequent. June. $ 



We find the segments of the calyx uniformly much longer 

 than the corolla. If the weather be fair, the large yellow 



