15b. Heterotheca villosa (Pursh) Shinners var. ballardii (Rydberg) Semple, Novon. 4: 53. 1994.
Chrysopsis ballardii Rydberg, Brittonia 1: 100. 1931
Stems ascending to erect, 22–50 cm, moderately to densely strigose, eglandular, often abundantly long-hirsute. Distal cauline leaf blades oblong, (18–)22–34(–42) × 4.3–9.3(–12.5) mm, little reduced distally, bases rounded, margins flat, faces moderately strigose (hairs usually not obscuring faces, 20–56(–70)/mm 2 ), eglandular. Heads (2–)4–16(–24), in corymbiform arrays. Peduncles (5–)12–47(–67) mm, moderately to densely hispido-strigose, eglandular; bracts subtending heads leafy, oblanceolate, often exceeding involucres. Involucres broadly campanulate, (5.5–)6.5–9.3 mm. Phyllaries narrowly triangular-lanceolate, moderately to densely strigose, eglandular to sparsely glandular, margins often reddish purple distally. Ray florets (12–)17–30 (avereaging 21), laminae (8.5–)9.9–14.5 mm (averaging 11.5 mm; showy). 2n = 36.
Flowering (Jun–)Jul–Aug(–Oct). Dry sandy clay, thin silty loam, sandy loam, gravel soils, dry, rocky, granite-gravel soils, prairies, fields, roadsides, railroad rights-of-way; 300–2300 m; Alta., Man., Ont., Sask.; Colo., Minn., Mont., Nebr., N.Dak., S.Dak.
Variety ballardii grows in the northeastern Great Plains; it is rare and probably introduced in Colorado, Montana, and northwestern Ontario. In its typical, large-leaved and many-rayed form, var. ballardii is quite distinct. It is distinguished by its rounded leaf bases, indument of short hairs, eglandular, and large, many-rayed heads often subtended by one or more large, narrow, leaflike peduncle bracts. Plants of var. ballardii are sufficiently similar to those of var. foliosa that the two taxa might be treated as convarietal under the name var. foliosa. V. L. Harms (2003) treated the Saskatchewan plants as members of a more broadly defined var. villosa.