Asteraceae, the daisy, sunflower, or composite family.
Plant: Erect, branching plant, 1'-4', with coarsely toothed compound leaves, and small yellow flowers heads surrounded by leafy bracts. Stems often pinkish or reddish. Annual.
Flowers: Small yellow heads, about 3/8" wide, surrounded by leafy, rather irregular, outer involucral bracts that may be several times as long as the diameter of the disk. The disk sometimes appears to be bordered by 5-8 tiny ray flowers, but the head is actually considered to consist solely of disk flowers. The petal-like structures are called "ligules" and are not considered to arise from ray flowers.
Leaves: Opposite, compound, with 3-5 lanceolate to narrowly ovate, coarsely toothed leaflets, to 4" long.
Fruit: Small "Tickseeds" that stick to hair and clothing.
Habitat: Fields, weedy spots.
The common name arises from the seeds, which somewhat resemble ticks, and
stick tightly to clothing and fur.
Where to find it:
I have found it in weedy thickets along the northeast side of the pond.