Malva rotundifolia L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Much like no. 5 [Malva neglecta Wallr.] in aspect; pedicels often shorter, but generally at least 10 mm in fr; pet mostly 4–5 mm, slightly if at all longer than the sep; mature carpels 8–11, commonly 10, glabrous or hairy, conspicuously rugose-reticulate on the back and radially veined on the lateral faces, the margins sharply angled but not winged, the whole head of carpels approximately circular in outline; central depressed area one-fifth the diameter of the head; 2n=42. Native of Europe; widely established as a weed in w. and s. U.S., and local with us. (M. pusilla)