Ahh, valiant hawkweed! Bravely it grows in dried out lawns, thin soils and rarely mowed fields, shooting up to flower and seed before the mower returns. It’s like a little piece of the prairie (though this is likely an introduced species from overseas). Hieracium is the genus, but I have not yet taken the time to key out the species for this particular one. It’s probably the common Field Hawkweed. Perhaps tomorrow I’ll beat the mower with enough time to key it out.
Update: I did in fact beat the mower, but not by much. Per my Newcomb’s Wildflower Guide it is Field Hawkweed, Hieracium pratense. The very hairy stems and clustered blooms are important features. Interestingly, not five feet away is a patch of another species, Common Hawkweed, Hieracium vulgatum. It is shorter, with larger blossoms that are somewhat branched but not packed into tight clusters as above. Neither species is native to America.
The image was captured with a Nikon D90 and Nikkor 70-300mm AF-S ED VR. I took advantage of the foreshortening effect of telephoto to bring a second plant into the background.