302 CARDUACEAE. 



elongate. Ray-flowers often numerous: corollas with a long tube and a narrow 

 yellow ligule. Disk-corollas with a eylindric- funnelform throat and a long tube: 

 lobes lanceolate. Anthers longer than the filaments. Pappus of several capil- 

 lary scabrous bristles. 



1. I. Helenium L. Plants 5-20 dm. tall, pubescent: blades of the cauline 

 leaves oblong-lanceolate to ovate, mainly 9-20 cm. long: inner bracts of the 

 involucre 15-17 mm. long: ligules of the ray 2-3 cm. long: achenes 4-5 mm. 

 long. — Occasional, on roadsides and in fence rows. Nat. of Eu. — Sum. — 

 Elecampane. 



25. POLYMNIA L. Perennial widely branched herbs. Leaves opposite 

 or mainly so: blades broad, pinnately veined. Heads inconspicuously radiate. 

 Involucre small, double, the outer series of bracts loose, the inner ones variously 

 shaped. Ray-flowers inconspicuous, the corollas with pubescent tubes and 

 white, greenish, or pale-yellow, wide ligules. Disk-flowers with long abortive 

 ovaries, the corollas with broadly funnelform throats and relatively long, ciliate 

 lobes. Stigma stout, thickened under the tip. Anther-body broader than the 

 appendage. Achenes slightly obcompressed, not oblique, 3-ribbed. Pappus 

 wanting. 



1. P. canadensis L. Stems 5-15 dm. tall: leaves 1-2 dm. long; blades oblong, 

 oval, or ovate: intermediate bracts of the involucre short-acuminate: ligules 

 greenish or whitish, inconspicuous, or obsolete: achenes about 3 mm. long, 

 obtuse-angled. — Susquehanna valley. Rare, in rich soil. — Sum. — Leaf-cup. 



26. POLYMNIASTRUM Small. Perennial large herbs. Leaves oppo- 

 site: blades very broad, palmately veined. Heads conspicuously radiate. Invo- 

 lucre large, the outer series of bracts foliaeeous, the inner narrower. Ray- 

 flowers conspicuous, the corollas with pubescent tubes and yellow narrow 

 ligules. Disk-flowers with short abortive ovaries, the corollas with cylindra- 

 ceous throats and short, ciliate lobes. Stigma slender, not thickened under 

 the tip. Anthers shorter than the filaments, the body narrower than the 

 appendage. Achenes somewhat laterally compressed, oblique, finely striate. 



1. P. Uvedalia (L.) Small. Stems 1-3 m. tall: leaves 1-5 dm. long; blades 

 3-5-lobed or angled: outer bracts of the involucre ovate to elliptic, 9-14 mm. 

 long: ray-flowers with yellow ligules 15-20 mm. long: achenes 5-6 mm. long. 

 — Susquehanna valley, and along tributary streams. Occasional, in shaded 

 places. — Sum. — Leaf-cup. 



27. SILPHIUM L. Perennial, usually large, caulescent herbs, often resin- 

 ous. Leaves alternate or opposite: blades entire, toothed, or 1-2-pinnately 

 parted, sometimes connate-perfoliate. Heads radiate. Involucres campanu- 

 late or hemispheric, many-flowered: bracts broad, in few series. Receptacle 

 flat or nearly so, with numerous bractlets subtending the disk-flowers. Ray- 

 flowers pistillate, fruit-producing: corollas with a very short tube: ligules yel- 

 low or rarely white. Disk-corollas with a very short tube, a long throat and 

 broad lobes. Achenes flat and broad, 2-winged. Pappus wanting or of 2 small 

 awns confluent with the wings of the achene. 



1. S. trifoliatum L. Plants 1-2 m. tall, the stem smooth and glabrous: leaves 

 mostly whorled in 3's; blades lanceolate to linear-lanceolate, 8-11 cm. long, 

 remotely serrate or nearly entire: heads often numerous: involucres campanu- 

 late ; bracts oblong-lanceolate to ovate and oblong, the inner ones obtuse : ligules 



