Mapping here is highly provisional. These colls. are difficult to identify and somewhat varied, with likely origin from hybrids (D, F, Y; FNA 8). They differ from collina as follows (FNA 8): styles and pyrenes 2 or 3 (versus usually 5); stamens 10-15 (versus usually 15-20); young lower leaf surfaces sparsely hairy or subglabrous (versus short-pubescent, puberulent, or pubescent). C. incaedua, with apparent colls. from HART and HOPK (KY), may be derived from hybridization of collina with calpodendron or with crus-galli. Similar colls. from CALL (MUR) and WHIT (GH) have been referred to C. disperma Ashe, which may be derived from collina or punctata (as one parent) and crus-galli (as the other). C. disperma reportedly differs from incaedua as follows (FNA 8): inflorescence branches glabrous (versus puberulent); anthers pink or red-purple (versus cream). The coll. from KENT (PH) has been determined as C. pratensis Sarg. (perhaps a small-flowered variant of collina) or C. peoriensis Sarg. (perhaps = disperma). These taxa are mostly poorly understood, with scattered distributions centered in midwestern regions.