This short-rhizomatous diploid (2n = 26) is a widespread tall herb of eastern woodlands and grasslands on various types of soil (F, W). C. tripteris is locally abundant in Ky., but largely restricted to localities with a history of grassy openings on seasonally damp acid soils. In contrast, W reported that it is typical of base-rich soils within more southeastern states. It appears to be highly palatable to deer and livestock, which may have reduced it within more intensively farmed fertile regions. There is significant variation across its range, but segregates have not been recognized in recent treatments. Some plants sold in Ky. as "native" have more dissected, bluish (versus yellowish) leaves with unusually narrow segments (ca. 0.5-1 cm versus 1-2 cm), and they flower earlier than wild plants (Jul-Aug versus Aug-Sep). These may be derived from a more western or southern provenance.