Oxalis corniculata. Did anyone else grow up calling this little yellow flowering creeper with heart-shaped leaves "sour grass"? I remember chewing on the stems of freshly picked sorrel as a kid, and the taste was reminiscent of pickles. (Caveat: I do not recommend taste-testing wildflowers without a certified nature guide along, and I especially do not recommend ingesting or even tasting any wildflower that may be in an area that has been treated with pesticides or other chemicals.)
Learn to identify one hundred species of flora within walking distance of your home! scsours began this challenge in July of 2008, and I was eager to hop on the bandwagon about a month later. I've remembered much and learned even more. It's been a fun but slow process. Spring has finally arrived here in Massachusetts, and I will hopefully be posting often soon.