This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flower-heads - Golden yellow, about 3/4 in. across, borne on slender peduncles in a loose, leafless cluster; rays 8 to 12 around minute disk florets. Stem: Slender, 1 to 2 1/2 ft. high, solitary or tufted, from a strong-scented root. Leaves: From the root, on long petioles, rounded or heart-shaped, scalloped-edged, often purplish; stem leaves variable, lance-shaped or lyrate, deeply cut, sessile.
Flowering Season - May - July.
Distribution - Gulf States northward to Missouri, Ontario, and Newfoundland.
While the aster clan is the largest we have in North America, this genus Senecio is really the most numerous branch of the great composite tribe, numbering as it does nearly a thousand species, represented in all quarters of the earth. It is said to take its name from senex = an old man, in reference to the white hairs on many species; or, more likely, to the silky pappus that soon makes the fertile disks hoary headed. "I see the downy heads of the senecio gone to seed, thistle like but small," wrote Thoreau in his journal under date of July 2d, when only the pussy-toes everlasting could have plumed its seeds for flight over the dry uplands in a similar fashion. Innumerable as the yellow, daisy-like composites are, most of them appear in late summer or autumn, and so the novice should have little difficulty in naming these loosely clustered, bright, early blooming, small heads.