SAussuBEA COMPOSITAE 381 



ARCTIUM 



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

 ceptacle flat, fimbrillate or with persistent chaflf. Corollas with 

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

 form 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, bear- 

 ing numerous corymbosely cymose heads : leaves membranaceous, ovate 

 and oblong-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-cori- 

 aceous : 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 among 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, 

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

 branches. Involucre globular ; its bracts slender-subulate or aris- 

 tiform and spreading above the broader appressed base, hooked 

 at tip, imbricated in several series. Receptacle flat, densely se- 

 tose. Anthers sagittate at base. Filaments glabrous. Achenes 

 oblong, somewhat compressed and 3-angled, truncate. Pappus of 

 numerous short and rigid or chafify '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- 

 peduncled, 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 CARDUUS L. 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 maturity some- 

 times campanulate, the mostly narrow bracts imbricated in many 

 series, more commonly tipped with a spine or cuspidate point. 

 Receptacle flat, fleshy, densely clothed with bristles. Filaments 

 commonly papillose-hairy, distinct. Anthers sagittate at base, 

 the auricles frequently, extended with tails. Style filiform, some- 

 times thickened, or with a ring or node at the base of stigmatic 

 portion. Achenes glabrous, thick-walled, obovate or oblong, more 



