Barbarea vulgaris

The afternoon turned dark and wind-chilled as I set out after my unknown little plant. In mind was that just yesterday as I walked towards the main entrance of work that I'd passed by dozens of my mystery plant sprouting from the lawn. Was I being taunted, I wondered.

Today I was greeted by a field full of specimens in flower! Unlike my earlier find, these has very little purple in stem and leaf. 

Once home, with images loaded and my browser pointed to the Connecticut Botanical Society, the identification was made in seconds. Barbarea vulgaris, commonly named Bittercress, Yellow Rocketcress, and on and on.

Notice the four-petaled flower that Mike advised I watch for. And, he was spot on suspecting this was a member of the Mustard family. Well done, and many thanks, Mike! And thanks go out to Gretchen as well for all her scouting work!

From The Entomologist:

"I was walking this afternoon beside the Blackwater, a small stream which flows through our valley, when I observed a common hive bee hanging, as I supposed, by the abdomen, from the blossom of a yellow cress, which is abundant there, Barbarea vulgaris. Accordingly, I picked the blossom and examined it more closely, as the position of the bee was peculiar, and I did not think it was dead. As it did not move, I at first thought it must have been detained a prisoner by some viscid fluid peculiar to the plant. I found, however, that in reality it was being tightly held by the falces of a bright yellow spider, so exactly the colour of the yellow blossom of the Barbarea vulgaris that at first (1 know something of botany) I mistook the yellow legs of a spider for the multifid stigma of the blossom."

Newman, Edward, The Entomologist: an illustrated journal of general entomology, Volume 5.  London, 1870-1. 315. Web. Google Book Search. 30 Apr 2011.