Yellow Coneflower (Ratibida pinnata)
Also called Gray-Headed Coneflower or Pinnate Coneflower. This is a rare plant in Pennsylvania, though not farther west, and certainly not rare in this hillside clearing in Scott Township, where these flowers were blooming in late July. The flower heads are distinctive: a thimble-shaped cone, starting greenish-gray and becoming brown as the disc florets bloom, with long drooping yellow rays that flutter in the breeze. The leaves are finely divided.
Gray places this species in the genus Lepachys. This is a curious example of the rule of priority in botanical nomenclature. The famous (and famously difficult) botanist, archaeologist, ethnographer, historian, journalist, explorer, philologist, unlocker of the secrets of the Maya, and proto-evolutionist C. S. Rafinesque described the genus Ratibida in 1818; a year later, he described the same genus in a different publication as Lepachys. Thus he has the peculiar distinction of having beaten himself to the naming of his own genus.
LÉPACHYS Raf. Heads many-flowered; the rays few, neutral. Involucral bracts few and small, spreading. Receptacle columnar; the chaff truncate, thickened and bearded at the tip, partly embracing the flattened and margined achenes. Pappus none or of 2 teeth. — Perennial herbs, with alternate pinnately divided leaves; the grooved stems or branches naked above, bearing single generally showy heads. Rays yellow or party-colored, drooping; disk grayish. (Name from lepis, a scale, and pachos, thick, from the thickened tips of the chaff.)
L. pinnàta (Vent.) T. & G. Hoary with minute appressed hairs, slender, 0.6-1.5 m. high, branching; leaflets 3-7, lanceolate, acute ; disk ellipsoid, much shorter than the large (6 cm. long) and drooping light-yellow rays. (RatibidaBarnhart.) — Dry soil, w, N, Y, to Minn., Neb., and southw.; also locally adventive eastw. June, July. — The receptacle exhales a pleasant anísate odor when bruised.