Wild Lettuce,  Lactuca canadensis
Asteraceae or Sunflower Family

Tall (up to 8 feet), coarse, weedy plant.  Small flower heads in large, branching loose clusters.  Each head like a tiny dandelion, opening briefly, yellow or reddish yellow.  Producing a small dandelion-like seedhead.  Leaves are very variable, often deeply lobed, often toothed, sometimes nearly entire.  Leaf bases may or may not clasp the stem.  Blooms in late summer.

A weedy native, fond of roadsides.  Occasional along Wildwood Drive and the bikeway.

Prickly lettuce (L. serriola), an alien, is similar but has spiny teeth on the leaves.  Other similar plants do not get so tall. Both species are in the same genus as cultivated salad lettuce (L. sativa).