Stems stout, to 1 m, very hirsute, especially below; lvs highly variable, but their lfls or lobes mostly obovate or oblong, distinctly cuneate at base; lower lvs on long petioles, the principal lfls often mingled with minute ones; lfls mostly incised-serrate; pet yellow, about equaling or slightly exceeding the sep; achenes numerous, ca 200 or more, divaricately hispid about the summit, otherwise glabrous or appressed-hairy; basal segment of the style often hirsute below; terminal segment conspicuously short-hirsute; receptacle glabrous or merely short-hispid; 2n=42. Swamps and wet meadows; interruptedly circumboreal. Amer. plants, the var. strictum (Aiton) Fernald, as here described, occur from Nf. and Que. to Yukon, s. to N.J., Ind., Ill., Io., and N.M. May-July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
All of my specimens are from the lake area where I have found it infrequently in marshes, tamarack bogs, and ditches. I have a specimen from Lagrange County with this note: "This plant had 10-12 petals to a flower and nearby plants also had more than 5 petals to a flower. Only one plant with the normal 5 petals." Sometimes the inner row of petals is much reduced in size. This species has been reported 4 times from Clark and Jefferson Counties, the authors saying: "In meadows." Doubtless these authors meant hayfields because meadows, in the botanical sense, do not occur there. I do not believe this species occurs there but what these authors had at hand I can not determine. The manuals used by them to distinguish the species are definite as far as this species is concerned. More intensive collecting in southern Indiana may reveal the plant in a different habitat.
Geum aleppicum has flowers with jointed styles, with the upper part less than half the length of the lower segment. It is found in moist wooded areas at middle elevation. It looks very similar to Geum macrophyllum var. perincisum. There are some differences in leaf shape, but the best field character is the presence of hairs obvious with a hand lens on the distal style segment on Geum aleppicum and missing on the style of Geum macrophyllum var. perincisum.