This species is poorly understood but appears widely scattered in eastern states, mostly east of the Mississippi Rv.. on acid soils in wooded hills within and around the Appalachian regions, with little on the Gulf Coastal Plain (K, Lance 2014). Variation and distinction from macrosperma remain unclear; both may be generally tetraploid but more data are needed. J.B. Phipps (FNA 9) presented a much narrower concept of iracunda, largely restricting it to the Coastal Plain from La. to Va. (FNA 9), with earlier flowering, less glandular petioles, and generally smaller leaves. But its definition can be extended to include more robust northeastern and Appalachian plants (Gl, F, HFG), with leaves relatively broad (C. silvicola Beadle) or more coarsely lobed (C. brumalis Ashe), or with glabrous leaves and larger flowers (C. populnea Ashe but see FNA 9), or with larger flowers and fruits (C. beata Sarg. but see FNA 9). C. iracunda (and other taxa in Silvicolae) can appear transitional between macrosperma (or its allies) and pruinosa (or its allies), with some suggestion of hybrid origin. Flowering appears to be relatively sparse in the wild (based on herbarium colls.), and R. Lance (pers. comm.) has found unusually low germination rates for seeds, but these plants clearly do still spread in small numbers within Ky. Variety status has been suggested by some authors, with C. macrosperma var. demissa (Sarg.) Eggl. a potential name, but some 33 synonyms are provisionally included at GH. Based on F, Gl, SC, W, Lance (2006, 2014), A. Haynes (pers. comm.) and examination of many collections (including GH, MO & NY), iracunda differs from macrosperma as follows: fruits less succulent; flowering usually before leaves fully formed (versus often fully formed); leaves smaller on average (blades 1.5-6 cm long versus 3-8 cm), short-hairy to glabrate above when young (versus scabrate), more deltoid in outline (versus ovate), firmer to "subcoriaceous" and more bluish; leaf lobes not distinctly acuminate and outwardly turned (versus slightly reflexed in macrosperma); petioles often distinctly winged, shorter on average (7-20 mm versus 10-30 mm); spines usually shorter, more slender and blackish (versus grayish).