COMPOSITAE. 945 



if. POifTNIA L'Her. 



Perennial glabrous herbs, with striate or angled stems, alternate entire sessile, 

 or clasping leaves, and numerous rather large heads of both tubular and radiate 

 flowers, paniculate, or solitary at the ends of the branches. Involucre hemispheric 

 or broadly campanulate, its bracts scarious- margined, imbricated in few series, 

 the outer slightly shorter. Receptacle convex or conic, foveolate. Ray-fiowers 

 pistillate. Disk-flowers perfect, their corollas elongated, 5-lobed. Anthers obtuse 

 and entire at the base. Style-branches flattened, their appendages short, lanceo- 

 late. Achenes flattened, obovate, their margins thickened or narrowly winged, 

 glabrous or nearly so. Pappus a series of short scales, usually with 2-4 slender 

 rigid bristles. [Named for James Bolton, an English botanist of the i8th cen- 

 tury.] As here limited, the genus consists of the 4 following species, with perhaps 

 a fifth in Oregon. 



Disk about 4 mm. broad; leaves linear. I. B. diffusa. 



Disk 6-12 mm. broad; leaves lanceolate. 



Leaves narrowed at the base, sessile, not decurrent on the stem. 



Involucre-bracts lanceolate, acute. 2. B. asteroides. 



Involucre-bracts spatulate, obtuse, or mucronate. 3. B. latisquama. 



Stem-leaves, and sometimes those of the branches, decurrent, sagittate. 



4. B. decurrens. 



1. Boltonia diffusa Ell. PANICLED BOLTONIA. (I. F. f. 3728.) Paniculately 

 much branched, 6-20 cm. high, the branches very slender or filiform. Leaves 

 acutish, the larger 3-5 cm. long, 4 mm. wide, those of the branches very small and 

 subulate; heads about 4mm. high; rays usually white, 2-4 mm. long; involucre 

 broadly campanulate, its bracts oblong or oblong -lanceolate, acutish or obtuse; 

 achenes obovate, narrowly winged; pappus of several short scales and 2 subulate 

 bristles shorter than the achene. In dry soil, southern 111. to Tex., east to S. Car. 

 and Fla. Aug.-Oct. 



2. Boltonia asteroides (L.) L'Her. ASTER-LIKE BOLTONIA. (I. F. f. 3729.) 

 Rather stout, 6-24 dm. high, somewhat cymosely paniculate. Leaves lanceolate 

 to oblanceolate, sessile, 5-12 cm. long, 6-25 mm. wide, the upper linear-lanceolate, 

 smaller; rays white, pink or purple, 6-12 mm. long; involucre hemispheric, its 

 bracts lanceolate or oblong lanceolate, acute or acuminate; pappus of setose scales, 

 with or without 2-4 slender bristles nearly as long as the obovate or oval achene. 

 In moist soil, N. J. to Fla., west to Minn., Neb. and La July-Sept. 



3. Boltonia latisquama A. Gray. BROAD-SCALED BOLTONIA. (I. F. f. 3730.) 

 Similar to the preceding species and perhaps a variety or form of iL Leaves lan- 

 ceolate, acute, sessile; heads rather larger; rays blue-violet; bracts of the invo- 

 lucre oblong-spatulate, obtuse or mucronate; pappus of numerous small short broad 

 scales and 2 long bristles. Western Mo., eastern Kans. and Ark. Autumn. 



4. Boltonia decurrens (T. & G.) Wood. CLASPING-LEAVED BOLTONIA. 

 (I. F. f. 3731.) Stout, 9-18 dm. high, branched above. Leaves oblong-lanceolate 

 or elongated lanceolate, mucronate at the apex, those of the stem decurrent and 

 sagittate at the base. 7-15 cm. long, 12-16 mm. wide, those of the branches 

 smaller and merely sessile or some of them also decurrent; heads 5-6 mm. high; 

 involucre hemispheric; rays about 6 mm. long, violet or purple; pappus of several 

 or numerous short scales and 2 very slender bristles. In wet prairies, 111. and Mo. 

 Aug. -Sept. 



30. SERICOCARPUS Nees. 



Erect perennial herbs, with alternate leaves, and middle-sized heads of boih 

 tubular and radiate flowers, in terminal cymose panicles. Involucre ovoid, oblong, 

 or campanulate, its bracts coriaceous, with herbaceous or squarrose tips, imbricated 

 in several series, the outer shorter. Receptacle small, foveolate. Ray-flowers 

 white, pistillate. Disk-flowers mostly perfect, their corollas tubular, narrow, yel- 

 lowish or purplish, 5-lobed. Anthers obtuse and entire at the base. Style- 

 branches with lanceolate- subulate appendages. Achenes slightly compressed, 

 linear-oblong, i-nerved on each side, pubescent. Pappus of numerous capillary 

 scabrous bristles, the outer usually shorter. [Greek, silky fruit, referring to the, 

 achenes.] Four known species ? natives of N, Arn? 



