8AUS8UREA COMPOSITE 381 



ARCTIUM 



lucre imbricated in several series, mostly not appendaged. Re- 

 ceptacle flat, fimbrillate or with persistent chaff. Corollas with 

 slender tube, inflated throat and 5-cleft limb. Anthers with se- 

 tiform ciliate or villous tails. Pappus double, the outer of a few 

 short denticulate rigid distinct bristles; the inner of a series of 

 stout^ plumose bristles which are united at base. 



S. Americana Eaton Bot. Gaz. vi, 283. Stems rather stout, 2-6 feet 

 high, leafy to the top, lightly arachnoid when young, soon glabrate, bearing 

 numerous oorymbosely cymose heads: leaves membranaceous, ovate and ob- 

 long-ovate, acute, or acuminate, denticulate or dentate: radical and lower 

 cauline subcordate, on slender margined petioles, 4 inches long or more; 

 upper sessile, with acute base; uppermost lanceolate: heads 6-10 lines high: 

 involucre somewhat turbinate, pubescent; its bracts thin-coriaceous: in 4-9 

 ranks all pointless and obtuse, the outer successively shorter: corollas blue or 

 purple : receptacle naked, or bearing more or less copious setiform chaff 

 a,mong the flowers. In moist places in the high mountains, Oregon and 

 Washington. 



88 ARCTIUM L. Gen. n. 923. ( BURDOCK). 



Coarse biennial herbs with broad alternate petioled leaves and 

 rather large heads of purple or white tubular perfect flowers, ra- 

 cemose, corymbose or paniculate at the ends of the stems or 

 branches. Involucre globular ; its bracts slender-subulate or 

 aristiform and spreading above the broader appressed base, 

 hooked at tip, imbricated in several series. Receptacle flat, 

 densely setose. Anthers sagittate at base. Filaments glabrous. 

 Achenes oblong, somewhat compressed and 3-angled, truncate. 

 Pappus of numerous short and rigid or chaffy bristles, separately 

 deciduous. 



A. LAPPA L. Sp. 816. Stem stout, 2-9 feet high much branched, rough: 

 leaves thin, broadly ovate, pale and tomentose beneath, obtuse, entire re- 

 pand or dentate, mostly cordate, the lower often 18 inches long: petioles 

 solid, deeply furrowed: heads clustered or corymbose, sometimes long-pe- 

 duncled, 6-12 lines in diameter: bracts of the involucre glabrous or nearly 

 so, their spines spreading, the inner ones equalling the flowers. Common 

 in waste places. Naturalized from Europe. 



89 CARDUU8L. Gen. n. 925. (THISTLE) 



Stout herbs with alternate usually prickly leaves and large or 

 middle-sized heads of purple, red, white or pale yellow flowers. 

 Heads many-flowered ; the flowers all perfect and fertile, with 

 tubular corollas with deeply, often more or less unequally, 5- 

 cleft narrow lobes. Involucre globular, ovoid, or at matur- 

 ity sometimes campanulate, the mostly narrow bracts inbricated 

 i n many series, more' commonly tipped with a spine or cuspidate 

 point. Receptacle flat, fleshy, densely clothed with bristles. 

 Filaments commonly papillose-hairy, distinct. Anthers sagit- 

 tate at base, the auricles frequently extended with tails. Style 

 filiform, sometimes thickened, or with a ring or node at the base 

 of stigmatic portion. Achenes glabrous, thick-walled, obovate or 



