CARDUACEAE 1305 



17. Senecio AlabamSnsis Britton. Perennial, similar to S. tomentosus in habit, but 

 the stem and leaves glabrous or essentially so. Stem 3-5 dm. tall, with few elongated 

 branches above : leaves mainly basal ; blades narrowly ovate to ovate-lanceolate, firm, 

 finely veiny, the small teeth terminating in black glands : heads relatively few, showy ; 

 involucres 7-9 mm. high ; bracts more or less persistently cobwebby : ligules of the ray, 

 flowers deep yellow, 5-8 mm. long : achenes about 3 mm. long. 



In moist pine woods, Henry County, Alabama. Spring. 



18 Senecio Memmingeri Britton. Perennial, glabrous or nearly so. Stems soli- 

 tary or tufted, 3-6 dm. tall, corymbosely branched above, accompanied by tufts of basal 

 leaves : basal leaves 1-2 dm. long ; blades bipinnatifid, longer than the petioles, the seg- 

 ments oblong or obovate in outline, more or less cuneate at the base, coarsely toothed or 

 incised, the teeth entire or with 1 or 2 small teeth : blades of the stem-leaves similar but 

 usually more finely divided : heads usually numerous : involucres 5-6 mm. high : bracts 

 linear, the longer 5 mm. long, acute, scarious-margined : ligules of the ray -flowers yellow, 

 linear-oblong, 5-6 mm. long, 3-toothed at the apex : achenes grooved, 1.5 mm. long, pubes- 

 cent. 



On cliffs or in dry soil, mountains, of North Carolina and Alabama. Spring and summer. 



19. Senecio Millefolium T. & G. Perennial, early glabrate. Stems 3-7 dm. tall, 

 sometimes tufted, corymbose above : leaves conspicuous ; blades 6-15 cm. long, bipinnately 

 dissected into narrowly linear segments, those of the basal and lower stem-leaves petioled ; 

 heads several or many : involucres 5-6 mm. high ; bracts linear with lanceolate tips, 4-5 

 mm. long : ligules of the ray-flowers yellow, linear or linear-oblong, 2-4 mm. long : 

 achenes. 



On cliffs in the mountains, North Carolina and South Carolina. Summer. 



20. Senecio Fremdntii (T. & G.) Rydb. Woody, at least below, glabrous or 

 nearly so. Stems more or less branched, 3-18 dm. tall, copiously leafy : leaves 2-7 cm. 

 long ; blades, except some of those near the inflorescence, pmnately parted into 3-9 linear 

 or filiform-linear segments : heads showy : involucres cylindric, 8-10 mm. high ; bracts 

 linear, acute or acuminate : ligules of the ray-flowers about 10 mm. long : achenes 3.5-4 

 mm. long, finely pubescent. 



In dry soil, Nebraska to Texas and Mexico. Summer and fall. 



143. ARCTITJM L. 



Biennial, coarse caulescent herbs, with pubescent foliage. Leaves alternate : blades 

 often ample, entire, repand, or rarely laciniate or pinnatifid. Heads discoid, racemose, 

 paniculate or corymbose. Involucres ovoid to globose : bracts narrow, in many series, 

 each terminated by a slender hooked tip. Receptacle flat, densely bristly. Corollas tubu- 

 lar, white or purple. Filaments glabrous. Anthers sagittate at the base. Achenes some- 

 what flattened and 3-angled, ribbed, truncate. Pappus of numerous rigid or scale-like 

 short serrulate bristles. BURDOCK. CLOTBUR. 



1. ' Arctium minus Schk. Stems 4-16 dm. tall, striate, widely branched, rigid : leaf- 

 blades ovate, often broadly so, those of the lower cauline leaves 2-4.5 dm. long, those of 

 the upper smaller, all undulate or shallowly toothed, often crisped : heads often numerous : 

 involucres 1-1.5 cm. long at maturity : bracts glabrous or sparingly cottony, the outer with 

 spreading spine-tips, the inner with erect spines : achenes 4 mm. long. 



In waste places and on roadsides, nearly throughout the United States and southern British 

 America. Native of Europe. Summer and fall. 



144. CARDUUS L. 



Biennial or perennial caulescent or rarely scapose herbs, with pubescent, often woolly 

 foliage. Leaves alternate, sometimes chiefly or wholly basal ; blades toothed, lobed or 

 pinnatifid, the teeth or segments commonly spine-tipped. Heads discoid, homogamous or 

 rarely dioecious, solitary or several and variously disposed. Involucres ovoid to globose : 

 bracts in many series, wholly or partially spine-tipped. Receptacle flat or convex, bristly. 

 Corollas tubular, mostly purple, yellow or white. Filaments mostly pubescent. Anthers 

 sagittate at the base. Stigmas obtuse. Achenes flattened or 4-angled, glabrous, smooth, 

 sometimes ribbed. Pappus of slender plumose serrulate or smooth bristles in several series, 

 often united at the base. THISTLE. 



