Image credit Wikipedia.
Much of my running is not actually on trails but rather on the rural roads surrounding my home in Franklin County, PA. Pehaps the most common wildflower I see is the Common Chicory (Cichorium intybus).
I'm partial to blue flowers anyway, and to see a faint line of blue on the roadside stretching away as far as the eye can see is great. I'm also a fan of chicory because it grows along roadsides and waste areas, thriving where other plants would perish. It's definitely one tough plant.
Gotta throw in a poem here that I ran across by John Updike
("Chicory" from Americana and Other Poems. © Alfred A. Knopf, 2001):
Show me a piece of land that God forgot—
a strip between an unused sidewalk, say,
and a bulldozed lot, rich in broken glass—
and there, July on, will be chicory,
its leggy hollow stems staggering skyward,
its leaves rough-hairy and lanceolate,
like pointed shoes too cheap for elves to wear,
its button-blooms the tenderest mauve-blue.
How good of it to risk the roadside fumes,
the oil-soaked heat reflected from asphalt,
and wretched earth dun-colored like cement,
too packed for any other seed to probe.
It sends a deep taproot (delicious, boiled),
is relished by all livestock, lends its leaves
to salads and cooked greens, but will not thrive
in cultivated soil: it must be free.