Helianthus occidentalis Riddell

  • Authority

    Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

  • Family

    Asteraceae

  • Scientific Name

    Helianthus occidentalis Riddell

  • Description

    Species Description - Rhizomatous and often stoloniferous perennial 0.5-1.5 m; lvs basally disposed, the lower ones much the largest, with ovate to lance-elliptic or lanceolate, entire or subentire blade 6-15 × 2-8 cm, 1.5-5 times as long as wide, sharply set off from the long petiole, the others ± reduced and distant; disk yellow, 1-1.5 cm wide; invol bracts ciliolate, ± imbricate, lanceolate or lance-ovate, (1.5)2-3 mm wide, at least the inner with loose, slender tip; rays 10-15, (1-)1.5-3 cm; 2n=34. Dry, often sandy soil; Md. and DC. to Minn., s. to Ga., w. Fla., and Tex. Aug.-Oct. Appalachian plants, from DC., Md., and W.Va. to n. Ga., form the var. dowellianus Torr. & A. Gray (H. dowellianus), with glabrous or closely strigose lvs that are often not so quickly reduced upwards as in var. occidentalis; the basal and lowermost cauline lvs are often deciduous, and some of the lower cauline ones (but well above the base) are often fairly well developed. More western plants in our range, with scabrous to hirsute, more consistently basally disposed lvs, belong to var. occidentalis.

  • Common Names

    naked-stemmed sunflower