[Sidenote: =Senecio discoideus= (Hook.) Britton. _Northern Squaw-root._] Smooth except for the small tufts of wool in the axils of the lower leaves; stem rather stout, 1—2 feet tall. Basal leaves oval or ovate, thin, sharply dentate, abruptly narrowed into petioles longer than the blade; stem leaves few, small, more or less irregularly cut. Heads few or numerous, corymbose; bracts of the involucre narrowly linear, nearly ½ an inch high; rays very short or wanting; achenes smooth. Frequent throughout the Rockies on river shores and borders of woods and thickets; flowering in July. [Sidenote: =Senecio flavovirens= Rydb. _Western Balsam Groundsel._] Light or yellowish-green, slender, woolly in tufts at the base of the leaves or smooth in age; stem 12—18 inches high, striate, pale. Leaves 1—3 inches long, at the base obovate or broadly oval, generally tapering into the petiole but sometimes truncate at the base, obtuse, crenate or sinuate, light green; lower stem-leaves lanceolate in outline and petioled, the upper lanceolate or linear and sessile, deeply pinnatifid with narrow oblong or linear segments, cymes contracted, corymbose. Heads ¼ of an inch or more high; bracts linear, acute, yellowish-green and occasionally with brownish tips; rays pale yellow, ½ an inch long, 4-nerved or often lacking. In the lower valleys of the Rockies, on the borders of woods, thickets, and marshes; flowering in July. [Sidenote: =Senecio canus= Hook. _Silvery Groundsel._] Permanently silvery-hairy with felted hairs; stems several, 6—12 inches high from a woody base. Leaves sometimes all undivided, the radicle and lower from spatulate to oblong or roundish-oval, ½—1½ inches long, slender-petioled, sometimes laciniate-toothed, or pinnatifid. Heads of flowers few and terminal, ⅓ to nearly half an inch high; rays yellow, nearly ½ an inch long. In stony dry ground and slopes throughout the Rockies at the lower altitudes; flowering in June. [Sidenote: =Senecio lugens= Richards. _Black-tipped Groundsel._] More or less woolly when young, soon smooth; stem stout, 1—3 feet high. Basal and lower leaves oblong or oval, obtuse or acute, denticulate or dentate, 2—5 inches long, ½—1½ inches wide, narrowed into margined petioles; upper leaves few, sessile, small and bract-like. Heads of flowers several or numerous, corymbose, often short-peduncled, ½ to nearly an inch broad; involucre campanulate, ¼—⅓ of an inch high, its bracts lanceolate to oblong-lanceolate, acute, green with conspicuous black tips; rays 10—12, bright yellow, ½ an inch long. In moist soil at the lower altitudes throughout the Rockies; flowering in June. [Sidenote: =Senecio triangularis= Hook. _Giant Ragwort._]