This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual. Propagates by seeds.
Time of bloom: June to August.
Seed-time: August to October.
Range: Nova Scotia to Virginia, westward to the Mississippi River.
Habitat: Fields and waste places.
Fool's Parsley is acridly poisonous; its Greek name means "to burn," which indicates the sort of agony that its victims feel.
Root spindle-shaped like a radish, three to six inches long. Stem one to two feet tall, slender, smooth, branching by forking. Leaves very dark green, smooth, shining, twice or thrice ternately divided, the segments again finely cleft; they look very like those of the true Parsley, but, when crushed, have a disagreeable, fetid odor; the upper ones are nearly sessile, the short petioles much dilated at the base. Flowers white, unpleasantly scented, the large umbel without an involucre, but the umbellets having involucels of long, narrow, downward-turned bracts. The flowers of true parsley are yellow.
Fig. 211. -Fool's Parsley (sEthusa Cynapium). X 1/4.
United carpels ovoid, nearly as broad as long, each of the two having five sharply keeled ridges. These seeds may remain dormant in the soil for several years and should never be permitted to sow themselves. (Fig. 211.)
If the infestation is new, hand-pull as soon as discovered and destroy it. Being annual, it is necessary only to prevent seed development in order to suppress the weed.