An unimposing little weed, but it delights children by producing round, flat seedpods that look like coins. The lesson to be learned here is that adults do not judge plants as children do, and perhaps children have a better sense of what is valuable than adults have. This plant grew in a meadow near Cranberry, where it was blooming and already seeding in the middle of June.
Gray describes the genus and the species:
THLASPI [Tourn.] L. PENNY CRESS
Pod orbicular, obovate, or obcordate, flattened
contrary to the narrow partition, the midrib or keel
of the boat-shaped valves extended into a wing. Seeds
2-8 in each cell. Cotyledons accumbent. Petals
equal.—Low plants, with root-leaves undivided,
stem-leaves arrow-shaped and clasping, and small white
or purplish flowers. (Name from thlaein, to
crush, from the flattened pod.)
T. arvense L. (FIELD P. or MITHRIDATE MUSTARD.) Smooth annual; lower leaves wing-petioled, the upper sagittate-clasping; broadly winged pod 1.2 cm. in diameter, deeply notched at top; style minute. Waste places; not common, except along our northern borders, where too abundant and called “FRENCHWEED.” (Nat. from Eu.)