966 FLORA. 



white to rose, 4-8 mm. long. In dry soil, western Neb. to Kans., Tex. and Mex., 

 west to Cal. May-Aug. 



33. BRACHYACTIS Ledeb. 



Annual, nearly glabrous, somewhat fleshy herbs, with narrow chiefly entire 

 leaves, and small racemose or racemose-paniculate heads of tubular, or also radiate 

 purplish flowers. Involucre campanulate. Central flowers of the head few, perfect, 

 their narrow corollas 4-5 -toothed; outer flowers pistillate, usually in 2 series or 

 more, and more numerous than the perfect ones; style-appendages lanceolate; rays 

 very short, or none. Achenes 2-3-nerved, slender, appressed-pubescent. Pappus 

 a single series of nearly white bristles. [Greek, short rays.] About 5 species, 

 natives of western N. Am. and northern Asia. 



1. Brachyactis angustus (Lindl.) Britton. Rayless Aster. (I. F. f. 

 3808.) Stem usually sparsely pubescent, at least above, 1.5-6 dm. high, striate, 

 at least when dry. Leaves linear, fleshy, ciliate on the margins, acutish, entire, ses- 

 sile by a rather broad base, the basal (when present) spatulate; heads 8-12 mm. 

 broad; involucre campanulateor nearly hemispheric, 4-6 mm. high, its bracts linear 

 or linear-oblong, somewhat foliaceous, green, acute or obtuse, imbricated in 2 or 3 

 series, glabrous or slightly ciliate, nearly equal; rays none or rudimentary; pappus 

 soft and copious. In wet saline soil, or sometimes in waste places, Minn, to the 

 N. W. Terr., Utah and Colo. Found also about Chicago. July-Sept. 



34. MACHAERANTHERA Nees. 



Annual, biennial or perennial branched herbs, with leafy stems, alternate, 

 mostly serrate or pinnatifid leaves, the teeth or lobes usually bristle-tipped, and 

 large heads of both tubular and radiate flowers. Involucre of numerous series of 

 imbricated canescent or glandular bracts with herbaceous or foliaceous spreading or 

 appressed tips. Receptacle alveolate, the alveoli usually toothed or lacerate. Ray- 

 flowers numerous, violet to red or purple, pistillate. Disk-flowers perfect, their 

 corollas tubular, 5-lobed, yellow, changing to red or brown; anthers exserted, 

 appendaged at the tip, rounded at the base; style-appendages subulate to lanceo- 

 late. Achenes turbinate, narrowed below, pubescent. Pappus of numerous stiff 

 rough unequal bristles. [Greek, sickle-anther.] About 15 species, natives of west- 

 ern N. Am. 



Annual or biennial; leaves pinnatifid. 1. m. tanacetifolia. 



Perennial or biennial ; leaves sharply serrate. 2. M. sessilijlora. 



1. Machaeranthera tanacetifolia (H. B. K.) Nees. Tansy Aster. Dag- 

 ger-flower. (I. F. f. 3809.) Annual or biennial; stem glandular-pubescent, 

 often viscid, densely leafy, much branched and bushy, 3-6 dm. high. Leaves ses- 

 sile or short petioled, pubescent, the lowest 2-7 cm. long, 2-3-pinnatifid, their 

 lobes linear or oblong, acute or mucronate, the upper pinnatifid, those of the 

 branches sometimes entire; heads numerous, corvmbose-paniculate, 3-5 cm. broad; 

 involucre hemispheric, 8-12 mm. high, its bracts linear, glandular, imbricated in 

 57 series; rays 15-25, 10-16 mm. long, achenes villous. In dry soil, Neb. to Tex. 

 and Mex., west to Cal. June-Aug. 



2. Machaeranthera sessilifldra (Nutt.) Greene. Viscid Aster. (I. F. 

 f. 3810.) Stem usually stout, finely rough -pubescent or canescent, branched, and 

 viscid-glandular above, 3-6 dm. high. Leaves lanceolate, linear, or the lowest 

 spatulate, sessile, sharply incised-dentate, the larger 2-7 cm. long, the teeth bristle- 

 tipped; heads numerous, racemose, or corymbose above, 25-37 mm. broad, the 

 lower often nearly sessile; involucre broadly turbinate or hemispheric, 8-12 mm. 

 high, its bracts arute. imbricated in 6-10 series; rays 8-12 mm. long; achenes 

 narrow, appressed-pubescent. In dry soil, central and western Neb. July-Oct. 



35. ERIGERON L. 



Branching or scapose herbs, with alternate or basal leaves, and corymbose, 

 paniculate or solitary, peduncled heads, of lx)th tubular and radiate (rarely all tubu- 

 lar) flowers. Involucre hemispheric or campanulate, its bracts arrow, nearly 

 equal, imbricated in but I or 2 series in our species. Receptacle nearly flat, usually 

 naked. Ray-tlowers, in our species, white, violet or purple, pistillate. Disk- 



