184 COMPOSITE. 



more or less glomerate heads. Fertile flowers 59, loosely disposed on 

 a slender receptacle, their enclosing bracts cymbiform, firm except the 

 narrow hyaline tip. Sterile flowers involucrate by 5 larger bracts, these 

 ovate-lanceolate, tapering into a rigid incurved-uncinate cusp, persist- 

 ent and at length stellate-spreading. Achene ovate-fusiform, obscurely 

 decompressed, the pericarp distinct from the seed and faintly nerved. 

 Pappus none. 



1. A. fllaginens, Gray. Leaves linear to spatulate: heads capitate- 

 glomerate, the hooked empty bracts at maturity 34 in. long. In open 

 grounds; not common. 



23. PSILOCARPHUS, Nutt. Small usually depressed much branched 

 floccose annuals, with opposite leaves and globose heads sessile in the 

 axils or at the forks. Fructiferous bracts numerous, on the globular 

 or oval receptacle, cucullate-saccate, semiobovate or semiobcordate, 

 rounded at top, herbaceo-membranaceous, apex introrse, the ovate or 

 oblong hyaline appendage inflexed or erect. Achene loose within the 

 bract, oblong or narrower, straight, slightly compressed. Pappus none. 



1. P. ten ell us, Nutt. Prostrate, forming a dense mat 3 6 in. wide: 

 heads very many: leaves spatulate, % ^ in. long: fructiferous bracts 

 scarcely a line long: achene ovate-oblong. In rather low or shaded 

 grounds among the hills. May. 



2. P. bre vissimus, Nutt. Dwarf, with very few and rather large woolly 

 heads: leaves oblong or lanceolate, 2 5 lines long, seldom surpassing 

 the heads: achene cylindrical or slightly clavate, 1 line long. Plains of 

 the interior, in low places. May. 



24-. EVAX, Gtertner. Low but rigid, leafy, with heads axillary and 

 terminal. Bracts of the involucre and those of the receptacle subtending 

 the pistillate flowers from oblong to obovate, becoming coriaceous, 

 persistent, concave. Eeceptacle slender columnar from a broader base, 

 sparsely villous, the pistillate flowers and their bracts crowded at its 

 base; the summit bearing a whorl of 3 7 coriaceous obovate or rounded 

 open bracts subtending a few sterile flowers; these with cleft style but 

 no ovary. Achenes pyriform-obovate, somewhat obcompressed, very 

 smooth. Pappus none. 



1. E. caulescens (Benth.), Gray. Branching from the base, erect, 

 24 in. high; leaves spatulate, the blade ^ in. long, tapering to a 

 slender petiole as long: heads mostly solitary in the axils, a number 

 glomerate at summit, which is not specially leafy. Very common on 

 sterile hills along our northern border. May. 



2. E. acanlis, Greene. Stout and low, the very short branches horizon- 

 tal: leaves with short blade and greatly elongated petiole: head glomerate 

 at the ends of all the branches, none in the axils'. Moist plains near 

 Antioch, and southward. April June. 



