365 Urban Species. #139: Horseweed

[urbpan]

Urban species #139: Horseweed Conyza canadensis

When I imagine a weed, I imagine horseweed. Dandelion is charming, and garlic mustard is sinister, but horseweed is nondescript and ubiquitous. I have seen this plant (a member of the fleabane group, in the aster family) grow in sidewalk cracks, abandoned window boxes, and, fittingly, horse pastures. A native North American plant, it has been prized as an herbal medicine ingredient since prehistory, and was introduced to Eurasia in the 1600's. Horseweed is the only North American plant on the list of the top ten weeds of the northern hemisphere. Its inconspicuous flowers, as well as its propensity to grow in waste areas, give strength to this plant's designation as a weed.

Comments

[almeda.livejournal.com]

Aha. Not the one, then, as Zathras said. My backyard conning towers remain unclassified! :->

[urbpan.livejournal.com]

Is your plant possibly pokeweed?

[almeda.livejournal.com]

Nah, nah, very long straight leaves coming out in pairs, opposite, just like horseweed's, only it gets INSANE tall. No branching, just the one stem with those leaves coming out of it; I've never seen flowers but there must be some, because it gets glossy black berries (kind of like pokeweed's above) that just nestle one-per-junction between the leaves and the stem.