This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual and winter annual. Propagates by seeds.
Time of bloom: May to September.
Seed-time: Late June to October.
Range: Nova Scotia to Minnesota, southward to Florida, Texas, and Mexico. Habitat: Grain and clover fields, roadsides, and waste places.
Stem six inches to two feet tall, much branched. The weed sometimes becomes a tumbleweed because of this spreading growth.
Lower leaves pinnatifid, spatulate in outline, with terminal lobe large and lateral lobes very small; stem-leaves merely toothed, not lobed, the upper ones becoming lance-shaped and often entire. Flowers white, very small, on elongating racemes that are finally six or eight inches in length, closely set with small, round, flattened, two-celled silicles, notched at the outer edge and each containing two reddish yellow seeds. Birds are very fond of these seeds and dispose of large quantities; they are a common impurity among clover seeds. Means of control the same as for Shepherd's Purse. (Fig. 121.)
Fig. 121. - Common Pepper-grass (Lepidium virginicum).
Fig. 122.- Green-flowered Peppergrass (Lepidium apetalum). X 1/2