Teasel (Dipsacus fullonum).
Teasels grow everywhere along roadsides; they can be
annoyingly invasive, but—like thistles—extraordinarily
beautiful if you take the time to admire the form and
structure. They are also much beloved by bees and
butterflies, who, if they could only talk, might wax
rhapsodic in their praises of the human pioneers who
first brought this plant to North America.
Cut-Leaf Teasel (Dipsacus laciniatus).
Very similar to the ordinary Teasel (Dipsacus
fullonum), but with white flowers rather than
pink ones. In Gray’s time it was known in the North
American wild only around Albany, but has since spread
from New York to Pennsylvania and much of the Midwest.
In Pittsburgh, it seems to be established especially
along long-distance expressways, with large stands
along Interstate 79 in Robinson Township and more
along the Pennsylvania Turnpike