This is widespread in varied disturbed habitats across eastern and central North America. It is potentially perennial but often short-lived or perhaps annual (Lovett-Doust et al. 1985); it does not consistently have rooting nodes, stolons or rhizomes, but it can often forms mats when disturbed and it spreads much by seed. It has been frequently confused with stricta, which tends to occur in more open habitats; see notes under that species. Early reports from Ky. appear to have generally named dillenii as "stricta". Gm (1914) noted under that name: "A common plant in cultivated ground and lawns... Smaller than O. corniculata [true stricta], the peduncles bearing only two flowers." O. dillenii and its weedy allies (florida, stricta, corniculata) are distinct from the generally more conservative eastern species of Oxalis (grandis, illinoensis, macrantha, ?colorea, ?texana) in their generally smaller flowers (with petals ca. 5-10 mm long versus 10-20 mm), which usually lack red lines in the throat (versus with at least faint lines present). Also dillenii and its weedy allies are usually homostyllous or slightly heterostylous (versus distinctly tristylous or in macrantha distylous). Compared to all other eastern species (excepting texana), dillenii has distinctive pubescence on stems (Nesom et al. 2014, W): "evenly strigose from base to peduncles and pedicels" (versus "pilose to villous to nearly glabrous, rarely strigose and then only on peduncles or pedicels"). Also, in dillenii (but unlike stricta and corniculata) seeds are "brown with definite white lines along the (7-) 8-10 (-12) transverse ridges" (Lovett-Doust et al. 1985).