288 



CICHORIACEAE. 



[Vol. hi. 



22. NABALUS Cass. Diet. Sci. Nat. 34: 94. 1825. 



Perennial, herbs with alternate, mostly petioled, dentate lobed or pinnalifid leaves, or the 

 upper auriculate and clasping, and numerous small heads of ligulate white yellowish or 

 purplish flowers in open or spike-like terminal panicles, or also in axillary clusters, usually 

 drooping. Involucre cylindric, usually narrow, its principal bracts in i or 2 series, nearly equal, 

 with a few smaller exterior ones at the base. Receptacle flat, naked. Rays truncate and 

 5 toothed at the summit. Style-branches slender. Achcnes oblong or narrowly columnar, 

 truncate, terete or 4-5-angled, mostly lo-ribbed. Pappus of copious rather rigid simple white 

 to reddish-brown bristles. [Modern Latin, from an Indian name for Rattlesnake-root.] 



About 20 species, natives of America and Asia. Besides the following, another occurs in north- 

 west America. Known by the general name of Rattlesnake-root or Drop-flower. The European 

 and African genus Prenanthes I.., is distinct from this. 



^- Bracts of the involucre glabrous, or with a few scattered hairs. 



Heads 5-7-flowered; involucre very narrow, light green, i" thick; pappus light straw-color. 



I. .X. al/issiniu!. 

 Heads 8-i6-flowered; involucre broader, green, purple or glaucous, ili"-^" thick. 



Leaves, or some of them, lobed, divided, or pinnatifid; involucre about i Ji" thick. 



Pappus deep cinnamon-brown. 2. JV. albns. 



Pappus straw-color or light browti. 

 Inflorescence paniculate. 



Involucral bracts with some stiff hairs, obviously shorter than the pappus; panicle- 

 branches divergent. 3. A' serpenlarius. 

 Involucral bracts glabrous, equalling the pappus; panicle-branches ascending, or 



upcurved. 

 Inflorescence thj'rsoid or glomerate. 



Leaves palmately lobed or divided; northern. 

 Leaves pinnately lobed or pinnatifid; southern. 

 Leaves irregularly dentate or denticulate, oblong; plant tall. 

 Leaves entire or denticulate; plant low, alpine; involucre 2\i"-2," thick. 



4. A'. Iri/oliolalus. 



5. N. nanus. 



6. N. virgalus. 



3. N. serpenlarius. 



7. N. Bootlii. 



i^ if^ Bracts of the involucre hirsute-pubescent. 



Inflorescence narrowly thyrsoid; heads 8-i6-flowered. 



Leaves and stem rough-puberulent or scabrous. 



Leaves and stem glabrous, glaucous. 

 Inflorescence corymbose-panicidate; heads 20-25-flowered. 



8. N. asper. 



9. N. racemosus. 

 10. N. crepidineus. 



I. Nabalus altissimus (L.) Hook. Tall White Lettuce. (Fig. 3576.) 



/l^&. 



Prenanthes altissima L. Sp. PI. 797. '753- 



Nabalus allissimus Hook. Fl. Bor. Am. i: 294. 

 1833- 



Glabrous, or sparingly hispidulous, not 

 glaucous; stem slender, 3°-"° high, green, 

 or sometimes purplish. Leaves thin, has- 

 tate, cordate, ovate,or the uppermost lanceo- 

 late, entire,denticulate, dentate or palmately 

 lobed or divided, most of them long- petioled, 

 the larger sometimes 6' long; heads very 

 numerous, in a narrow panicle, and often in 

 axillary clusters, 5-7-flowered, pendulous, 

 about 2" broad; inflorescence often narrow; 

 involucre narrowly cylindric, 5"-6" long, 

 about i" thick, green, glabrous, its principal 

 bracts about 5; flowers greenish or yellow- 

 ish white; pappus light straw-color. 



In woods and thickets, Newfoundland to 

 Manitoba, south to Georgia and Tennessee. 

 A plant from Missouri has bright brown pap- 

 pus. Called also Lion's-foot. Rattlesnake-root. 

 Ascends to 2500 ft. in the Catskills. July-Oct. 



