OF ARTS AND SCIENCES. 273 



* Involucres broadly triangular : bracts foliaceous : flowers nearly sessile. 



22. C. POLTGONOIDES, Torr. & Gray. Decumbent, villoiis-pubes- 

 cent: leaves and bracts narrowly oblanceolate ; floral bracts very 

 short : involucres 3-costate, with 3 stout broad divergent uncinate 

 teeth, exceeding the (1 line tube) long. — Near Placerville, California; 

 only by Rattan. 



23. C. KiGiDA, Torr. & Gray. Erect, low, dense, becoming rigid 

 and persistent : leaves and bracts ovate, tomentose beneath ; floral 

 bracts linear-subulate, stout and spinescent, 6 to 15 lines long: in- 

 volucres 6-costate, with 3 very unequal lanceolate carinate spinescent 

 or pungent teeth. — N. W. Nevada to S. E. California and S. Utah. 



* * Involucres cylindrical : bracts not foliaceous, subulate-setaceous : flowers 

 on slender pedicels : leaves tomentose beneath : low. 



24. C. CORRUGATA, Torr. & Gray. Leaves ovate : the involucres 

 strono-ly corrugated, 8-toothed : flowers white, included : stamens on 

 the middle of the tube. — Valley of the Lower Colorado. 



25. C. Watsoni, Torr. & Gray. Leaves narrowly oblanceolate : 

 bracts rarely foliaceous : the involucres obscurely corrugated, very un- 

 equally 5-toothed : flowers yellow, slightly exserted. — N. Nevada to 

 S. E. California. 



OxTTHECA iNERMis. Low and slender: leaves broadly oblanceo- 

 late, glabrous, with scabrous-ciliate margin : bracts linear-oblong, united 

 only at base, acute without awns, 2 or 3 lines long : involucres shortly 

 pedicelled, 4-parted nearly to the base, the oblong-lanceolate lobes 

 nearly equal, acute without awns, a line long : flowers rose-colored, 

 half a line long ; sepals oblong, the inner smaller and retuse. — Cali- 

 fornia, probably on Mount Diablo : collected only by Miss M. J. Ban- 

 croft. Remarkable for the total absence of awns, but otherwise with 

 the characters of the genus, and nearly allied to 0. dendroidea, Nutt. 



Amarantus (Pyxidium) blitoides. Prostrate or decumbent, the 

 slender stems becoming a foot or two long, glabrous or neaily so : 

 leaves broadly spatulate to narrowly oblanceolate, attenuate to a slender 

 petiole, an inch long or usually less : flowers in small contracted axil- 

 lary spikelets : bracts nearly equal, ovate-oblong, shortly acuminate, 

 1 to 1^ lines long, little exceeding the oblong obtuse and mucronulate 

 or acute sepals : utricle not rugose, slightly longer than the sepals : 

 seed nearly a line broad. — Frequent in the valleys and plains of the 

 interior, from Mexico to N. Nevada and Iowa, and becoming intro- 

 duced in some of the Northern States eastward. It somewhat resem- 

 bles the A. Blitum, Linn., of the Old World, and has been mistaken 



VOL. XII. (N. S. IV.) 18 



