This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Biennial or perennial. Propagates by seeds.
Time of bloom: June to September.
Seed-time: July to October.
Range: Ontario to Minnesota and Nebraska, southward to Georgia; also naturalized on the Pacific Coast.
Habitat: Fields, meadows, and waste places.
An escape from gardens where it has been cultivated for the fleshy, edible taproot, which, when cooked, has a flavor somewhat like oysters. Larger than the preceding species, with stems two to four feet tall, broader leaves, the peduncles dilated and hollowed for a space of two or three inches below the heads, which are purple, often three inches broad, the long, green points of the involucral bracts extending for about half their length beyond the rays, making an eight- to ten-pointed green star with a purple center, whence the name "Jerusalem Star." Achenes brown, fully a half-inch in length, ridged, and tubercled, the slender beak about an inch long, the tawny, funnel-formed, inter-webbed pappus nearly equal in length. The size and weight of the seeds of both this and the preceding species make them very readily removable when they appear as an impurity among other seeds.
Means of control the same as for the preceding species.