Thank you, Roger Tory Peterson

After trying to determine the name of the yellow flowers through repeated web surfing of wildflower identification sites with no success, I remembered that we had an old copy of A Field Guide to Wildflowers of Northeastern and North-central North America by Roger Tory Peterson and Margaret McKenny (acquired from Braman's grandparents when we helped clean out their house.)

Looking through the Yellow flowers section, I saw something that looked like our flower but it was a line-drawing not an actual photograph and I wasn't sure. So I looked up the name on Google and, lo and behold, our flower is Birdfoot Trefoil (Lotus corniculatus), which grows on roadsides, waste areas and fields.

See the Connecticut Botanical Society's site and the UMass Cooperative Extension site for better pictures than my own and more information.

Just goes to show that old-fashioned books can still be superior as a fast source of accurate and valuable information. (But I'll admit that I was glad to have the computer to verify my guess.)