13. Senecio Tomentosus Michx. Woolly Ragweed. Ashwort

Fig. 4622

S. tomentosus Michx. Fl. Bor. Am. 2: 119. 1803.

Perennial, more or less densely and persistently tomentose or woolly-canescent; stems rather stout, solitary, or sometimes tufted, 1°-2 1/2° high. Basal and lower leaves ovate-lanceolate, oblong or rarely spatulate, long-petioled, erect, very obtuse, 2'-6' long, -2' wide, crenate-dentate, narrowed or truncate at the base; stem leaves few and distant, small, linear-lanceolate or spatulate, crenate or rarely laciniate; heads several or numerous, corymbose, mostly long-peduncled, 8"-10" broad; involucre cylindric, or narrowly campanulate, its bracts linear-lanceolate, acute or acuminate, at length glabrate, with or without a few small outer ones; rays 10-15; achenes hispidulous, at least on the angles; pappus white.

In moist soil, southern New Jersey to Florida, Louisiana, Texas and Arkansas. April-June.

14. Senecio Plattensis Nutt. Prairie Ragwort

Fig. 4623

S. plattensis Nutt. Trans. Am. Phil. Soc. (II) 7: 413.

1841.

Perennial, similar to the preceding species, usually smaller-leaved, lower and less tomentose, or becoming glabrate in age, seldom over 1 1/2° high. Basal leaves oval, ovate or oblong, some or all of them often more or less pinnatifid, with the terminal segment much larger than the lateral ones, crenulate or dentate, long-petioled; stem leaves mostly smaller than the basal ones, usually pinnatifid; heads several or numerous, compactly or loosely corymbose, conspicuously radiate.

Indiana and Illinois to Ontario, North Dakota, Colorado, Missouri and Texas. April-June.

Senecio pseudotomentosus Mackenzie & Bush, of Missouri, differs in having the basal leaves mostly merely dentate.

14 Senecio Plattensis Nutt Prairie Ragwort 129414 Senecio Plattensis Nutt Prairie Ragwort 1295

15. Senecio Robbinsii Oakes. Robbins' Squaw-Weed

Fig. 4624

Senecio Robbinsii Oakes; Rusby, Bull. Torr. Club 20: 19. 1893.

Perennial, glabrous or very nearly so throughout; stems slender, 1°-2 1/2° high. Basal leaves long-petioled, lanceolate, obtuse or acute at the apex, cordate, subcordate or truncate at the base, usually thin, 2-4' long, 1/2'-1 1/4' wide, sharply dentate; stem leaves mostly pinnatifid or lobed, at least below the middle; heads several or numerous, slender-peduncled in an open corymb. 8"-10" broad; rays 6-12; achenes glabrous or pubescent; pappus white.

In swamps and mountain meadows, Nova Scotia to New Hampshire, Vermont and New York. June-Sept.

16. Senecio Aureus L. Golden Ragwort. Life-Root. Swamp Squaw-Weed

Fig. 4625

Senecio aureus L. Sp. Pl. 870. 1753.

Senecio pauciflorus Pursh, Fl. Am. Sept. 529. 1814.

Senecio gracilis Pursh, Fl. Am. Sept. 529. 1814.

Perennial, glabrous or very nearly so throughout; stems rather slender, solitary or tufted, 6'-2 1/2° high. Basal leaves cordate-ovate or cordate-orbicular or reniform, crenate-dentate, very obtuse and rounded, often purplish, 1'-6' long, with long slender petioles; lower stem leaves lanceolate or oblong, usually laciniate, pinnatifid or lyrate, the uppermost small, sessile, somewhat auriculate and clasping; heads usually several, 8"-10" broad, 4"-5" high, slender-peduncled in an open corymb; rays 8-12, golden-yellow; achenes glabrous; pappus white.

In swamps and wet meadows, Newfoundland to Florida, Ontario, Michigan, Missouri and Texas. Grundy-swallow. False-valerian. Root strong-scented. Races differ in size of plant, size of leaves and number of heads. May-July.

16 Senecio Aureus L Golden Ragwort Life Root Swamp 129616 Senecio Aureus L Golden Ragwort Life Root Swamp 1297

Senecio pseudaureus Rydb (S. semi-cordatus Mackenzie & Bush), of the Rocky Mountain region, differing by elliptic or broadly oblong basal leaves, ranges eastward into North Dakota and Missouri.