COMPOSITAE (COMPOSITE FAMILY) 871 



* * * Heads 5-lS-flowered, racemose or paniculate, commonly pendulous ; leaves 

 variable, mostly petiolate, the lower cordate or truncate or hastate at base. 



*- Involucre cylindrical (at least below the middle); bracts scarious-margined, 

 the outer numerous, short, 



++ Involucre of 6-8 primary bracts, S-12-flowered. 

 = Pappus deep reddish-brown. 



6. P. alba L. (WHITE LETTUCE, RATTLESNAKE-ROOT.) Smooth and glau- , 

 cous ; stem stout, usually purplish, 0.5-1.5 m. high, corymbose-panicled at ^>U\ 

 summit ; leaves angulate or triangular-halberd-forin, sinuate-toothed or 3-5-cleft, 



the uppermost oblong and undivided ; involucre whitish-green and purplish, 

 glaucous; flowers whitish. (Nabalus Hook.) Rich woods and thickets, s. 

 Me. to the Saskatchewan, s. to Ga., Ky., and 111. Late July-early Oct. 



= = Pappus whitish or brownish-white. 



a. Primary bracts scarcely as long as the pappus, the small outer ones 



lanceolate. 



7. P. serpentaria Pursh. (LION' S-FOOT, GALL-OF-THE-EARTH.) Stem smooth, 

 3-12 dm. high, usually purplish, corymbose-panicled at summit; leaves thick, 



variously lobed, often pinnatifid with blunt or rounded lobes, 

 or even entire, the lower on margined petioles ; heads chiefly 

 clustered at the tips of elongate branches ; involucre funnel- 

 form, cylindric below, its subherbaceous green or purplish 

 frequently setulose bracts abruptly spreading above the middle ; 

 flowers purplish, greenish-white, or cream-color ; achenes 

 1035. P. serpentaria. yellow-brown. (Nabalus Hook.) Dry open soil, e. Mass. 

 Heads x%. to Fla. and Ala. Sept., Oct. FIG. 1035. 



b. Primary bracts as long as the pappus, the small outer ones deltoid to ovate. 



8. P. trifoliolata (Cass.) Fernald. (GALL-OF-THE-EARTH.) Glabrous, 1.5-15 

 dm. high ; leaves thinnish, nearly all petioled ; the lower mostly 3-divided or 

 angulate, occasionally uncleft or with the divisions finely dis- 

 sected ; inflorescence an elongate panicle, the heads clustered 



at the tips of comparatively short ascending branches or in the 

 upper axils ; involucre cylindric, glaucous ; its pale green or 

 purple-tinged primary bracts linear-lanceolate, acute, the inner 

 with broad scarious margins; outer calyculate bracts lance- 

 deltoid, rather firm, with pale hyaline margins, regularly 1036. P. trifoliolata. 

 imbricated, the longest 1.5-2.5 mm. long; achenes yellow- Heads x%. 

 brown. (Nabalus Cass.; P. serpentaria Man. ed. 6, in part, 

 not Pursh.) Thickets and woods, Nfd. and Que. to Del., Pa., and along the 

 mts. to Tenn. Aug., Sept. FIG. 1036. 



9. P. nana (Bigel.) Torr. Stem simple and strict, 0.5-7.5 dm. high ; leaves 

 much as in the preceding, very variable in outline; inflorescence a thyrse or 

 raceme, rarely somewhat paniculate or subcorymbose ; involucre thick-cylindric, 

 glabrous ; bracts lead-color or blackish ; the primary ones linear- to lance-oblong, 

 blunt or acutish, the inner with narrow scarious margins; outer calyculate 

 bracts ovate to ovate-lanceolate, blackish-green, herbaceous or fleshy, very 

 unequal, the longest 3-6 mm. long; achenes yellowish- to reddish-brown. 

 (Nabalus DC.; P. serpentaria, var. Gray; P. trifoliolata, var. Fernald.) 

 Rocky or mossy places, Lab. and Nfd. to the coast of N. S., and the higher mts. 

 of n. N. E. and n. N. Y. July-Sept. 



w- .*-* Involucre of 5 primary bracts, 5-6-flowered. 



10. P. altissima L. Smooth, tall and slender, 1-2 m. high ; heads in small 

 axillary and terminal loose clusters forming a long and wand-like leafy panicle ; 

 leaves membranaceous, all petioled, ovate, heart-shaped, or triangular, and 

 merely toothed or cleft, with naked or winged petioles, or frequently 3-5-parted, 



