352 LXXV. COMPOSITE. Xanthium. 



56. FILAGO. Tourn. 

 Apparently from the Lat. Jila, on account of the cottony fibres or hairs. 



Heads heterogamous ; involucre of a few villous scales ; marginal 

 flowers 9; receptacle columnar, naked at the apex, chaflFy at base; 

 achenia terete ; central ones with a hairy pappus. — Downy -canescent 

 herbs. Lvs. alter nate^i entire. 



F. Germanica. (Gnaphalium. Linn.) German Cud-weed. 

 St. dichotomous or proliferously branched above ; lis. linear-lanceolate, 

 acute, crowded, erect ; hds. few-flowered, in dense, capitate clusters, terminal 

 and lateral ; scales cuspidate, passing insensibly into the paleae of the receptacle, 

 each with a pistillate flower in the axil. — ® A European plant, sparingly natu- 

 ralized in fields and roadsides, Ms. Stem 6 — 10' high. Scales straw-color, with 

 a green line outside. July — Oct. 



57. ERECHTITES. Raf. 



Gr. cpc^^tj, to trouble ; the species are troublesome weeds. 



Flowers all tubular, those of the margin pistillate, of the disk per- 

 fect ; involucre cylindrical, simple, slightly calyculate ; receptacle 

 naked ; pappus of numerous fine, capillary bristles. — (D Lvs. simple, 

 alternate. Fls. corymbose.^ whitish. 



E. HiERACiFOLius. Raf. (Senicio hieracifolius. Linn.) Fire-aeeed. 

 St. paniculate, virgate; lis. oblong, amplexicaul, acute, unequally and 

 deeply toothed with acute indentmes ; inrol. smooth ; ach. hairy. — ® A well 

 known, rank weed, growing in fields, (Can. and U. S.) particularly and abun- 

 dantly in such as have been newly cleared and burnt over, and hence it is called 

 fire-weed. Stem thick and fleshy, branching, 3f high, roughish. Leaves of a 

 light green, large, irregularly cut into many deep and acute teeth. Flowers 

 terminal, crowded, destitute of rays, white. Involucre large and tumid at base. 

 Aug. Sept. 



58. XANTHIUM. 

 Heads heterocephalous. Sterile. — Involucre imbricate ; anthers 

 approximate, but distinct : receptacle chaffy. Fertile. — Involucre 2- 

 leaved, clothed with hooked prickles, 1 or 2-beaked, 2-flowered ; sta- 

 mens 0. — ® Coarse weeds u'ith alternate leaves. 



1. X. Strumarium. Clofvccd. 



St. unarmed, branching; lis. cordate, lobed, 3-veined, unequally serrate, 

 rough ; fr. elliptical, armed with uncinate, stiff" thorns, and ending with 2, spread- 

 ing, straight horns. — A coarse, rough plant, in old fields, &c., N. Eng, and Mid. 

 States. Stem branched, bristly, spotted, 2 — 3f high. Leaves large, on long 

 stalks, rigid. Sterile flowers few together, terminal, globular, green. Fertile, in 

 sessile, axillary tufts. Fruit a hard, 2-celled burr, near an inch long, covered 

 with stiff", hooked prickles, which, like those of the common burdock, serve to 

 disperse the seeds. Aug. ^ 1 



2. X. EcniNATUM. Murray. (X. macrocarpon. DC.) 



St. rough and strigose, spotted ; lis. scabrous, obscurely lobed, obtuse, 

 broad and subcordate at base, repand-toothed ; fr. oval, densely armed with ri- 

 gid, imcinate bristles ; horns incurved. — A very coarse plant in marshes near 

 the .seacoast, Mass. to Car. Stem thick, 1 — 2fhigh. Fruit very large, hairy. 

 Aug. — Oct. 



3. X. spiNosuM. Prickly Clotweed, 



St. branched; spines at base of the leaves triple, .slender; te. ovate-lanceo- 

 late, cuneate at base, petiolate, 3-lobed or dentate or entire, under surface and 

 veins above whitish, twice longer than the spines; inrol. oblong, with slender, 

 uncinate spines. — Roadsides and fields, Mass. to Penn. ! and Ga. Plant about 

 If high, very conspicuously armed with straw-colored spines f — 1' long. Heads 

 sessile, sterile in the upper, fertile in the lower axils. Sept — Nov. 



