This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual. Propagates by seeds.
Time of bloom: May to August.
Seed-time: June to September.
Range: Atlantic States from New Brunswick to Pennsylvania, naturalized from the Pacific Slope where it is native, and common as far east as Wyoming and Montana.
Habitat: Fields, roadsides, and waste places.
This plant not only has found its way East, but has gone abroad and is naturalized as a weed in northern Europe. Stem rather stout, six to eighteen inches tall, smooth, branching, and very leafy. Leaves pinnate, twice or thrice dissected into short, very narrow, and sharply pointed lobes: when bruised they have an odor suggestive of pineapples. Heads very numerous on short peduncles, without rays, the disk bluntly ovoid, greenish yellow; bracts of the involucre broadly oval, not quite half the length of the disk, green, with white, scarious margins. Achenes rounded oblong, faintly ribbed, often without a pappus but sometimes having an obscure marginal crown, bearing one or two small, oblique auricles.
Means of control the same as for Mayweed.