Several cultivated annual species, including those treated here, are ± weedy in habit and are occasionally found escaped in dumps and other disturbed places, though they seldom persist for long. The species thus far collected out of cultivation in Michigan have doubtless occurred at many places besides those mapped here on the basis of extant collections, and additional ones may be found. Papaver argemone L. is a weedy little annual from Europe with deeply pinnatifid leaves and with bristles on the broadly club-shaped fruit collected once from a field of crimson clover in Grand Traverse Co. (no collector in 1896, MSC); presumably as a contaminant in the seed and not actually established.
1. Petals mostly at least 5 cm long; plant a coarse perennial (non-flowering stems present).
2. Petals lacking a large black blotch or with a small, rounded or squarish blotch; leaves absent in the upper 1/3 of the stem; flowers lacking bracts.
2. Petals with a conspicuous oblong blackish blotch longer than broad; leaves extending unto upper 1/3 of stem; bracts present below flowers.
1. Petals less than 5 cm long; plant annual (all stems bearing flowers).
3. Plant coarsely hairy or bristly; upper leaves sessile but not clasping, scarcely if at all glaucous.
3. Plant usually glabrous; upper leaves strongly clasping the stem, very glaucous.
All species found in Papaver
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 17, 2017. http://www.michiganflora.net/genus.aspx?id=Papaver.