YELLOW ROCKET, Barbarea
vulgaris R. Br. 1, upper part of plant; 2, lower part
of plant; 3, pods; 4, flower; 5, seed; 6, root.
Winter annual, biennial, or perennial, reproducing
by seed, taprooted. Stems numerous, growing from a crown, upright,
1 to 2 feet (30 to 60 cm) tall, branched near top, smooth, and angular
or ridged. Leaves pinnately divided; basal leaves have a large terminal
lobe, are 2 to 8 inches (5 to 20 cm) long, and form a dense rosette; stem
leaves become progressively shorter with top leaves about 1 inch (2.5 cm)
long and less deeply lobed. Flowers bright lemon-yeIlow, 4-petaled
(typical mustard flower), borne in spikelike racemes on end of each branch.
Bloom in late April and early May. Pods about 1 inch (2.5 cm) long,
about 3/32 inch (2.4 mm) in diameter, nearly square in cross section. Seeds
light yellow to yellowish-brown, 1/32 inch (0.8 mm) long, ripening in May
and early June. Found along roadsides, in pastures, and in timothy,
clover, and alfalfa fields, where it matures before the crop is cut. Seeds
live several years in the soil. Also known as winter cress.