GENUS 20. THISTLE FAMILY. 495 
4. Boltonia dectrrens (T. & G.) Wood. 
Clasping-leaved Boltonia. Fig. 4278. 
Bol-onia glastifolia var. (?) decurrens T. & G. Fl. N. 
A. 2: 188. 1841. 
Boltonia decurrens Wood, Bot. & Flor. 166. 1870. 
Boltonia asteroides var. decurrens Engelm.; A. Gray, 
Syn. Fl. 1: Part 2, 166. 1884. 
Stout, 3°-6° high, branched above. Leaves oblong- 
lanceolate or elongated-lanceolate, mucronate at 
the apex, those of the stem decurrent and sagittate 
at the base, 3-6’ long, 6-8” wide, those of the 
branches smaller and merely sessile or some of them 
also decurrent; heads 23-3” high; involucre hemi- 
spheric; rays about 3” long, violet or purple; pap- 
pus of several or numerous short scales and 2 very 
slender bristles. 
In wet prairies, Illinois and Missouri. Aug.—Sept. 
Perhaps a race of B. asteroides. 
3o. SERICOCARPUS Nees, Gen. & Sp. Ast. 148. 1833. 
Erect perennial herbs, with alternate leaves, and middle-sized heads of both 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, yellowish 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 North America. Besides the following, another occurs on the 
northwestern coast of North America. Type species: Sericocarpus solidagineus (Michx.) Nees. 
Leaves entire, linear, spatulate, or obovate, rigid. 
Glabrous, or nearly so; leaves linear or linear-spatulate. 1. S.linifolius. 
Puberulent or scabrous ; leaves obovate. 2. S. bifoliatus. 
Leaves dentate, oblong, or obovate, thin. 3. S. asteroides. 
1. Sericocarpus linifolius (L.) B.S.P. Narrow-leaved White-topped Aster. 
Fig. 4279. 
Conyza linifolia L. Sp. Pl. 861. 1753. 
Aster solidagineus Michx. Fl. Bor. Am. 2: 108. 
1803. 
Sericocarpus solidagineus Nees, Gen. & Sp. Asf. 
149. 1832. 
Sericocarpus linifolius B.S.P. Prel. Cat. N. Y. 26. 
1888. 
; Glabrous or very nearly so throughout; stem 
rather slender, striate, 1°-23° high. Leaves 
linear or linear-spatulate, spreading, faintly 
3-nerved, thick, entire, obtuse at the apex, nar- 
rowed at the base, 1’-2’ long, 13-3” wide, ses- 
sile, or the lowest on short margined petioles, 
their margins scabrous; heads about 37-4” 
high, clustered in 2’s-6’s at the ends of the 
cymose branches; involucre oblong-campanu- 
late, 2-33” long, its bracts oblong, obtuse, the 
outer with somewhat spreading or reflexed 
green tips, the inner scarious and often lacer- 
ate or ciliate at the apex; rays 4 or 5, about 
5” long; pappus white. 
In dry, usually sandy soil, Maine to Ohio, Geor- 
gia and Louisiana. Erroneously recorded from 
Canada. June-Sept. 
