This weed came across my desk a week ago. I promptly went home and found more of it at my own home. Very common around these parts this time of year.
Hairy bittercress. This is a winter or a summer annual and several generations may be produced in a growing season. Flowers are most prolific in spring. Note the long slender fruit, or silique, which ascends past the flowers. This is a weed of nurseries, landscapes, agricultural fields, turf and greenhouses.