A few Apocynum cannabinum were beginning to bloom along the rail trail down from Masontown on June 17. I didn't get off many shots, and this blurry specimen is the best of those.
The common name of this native plant is Dogbane, but it is also known as Hemp Dogbane, Indian Hemp, or Rheumatism Root. Aside from the poisonous nature of this plant, its other names reflect its use as a source of fiber (Indians used it to make string and fabric) and as an herbal remedy for rheumatism (also, apparently, for syphilis, intestinal worms, fever, asthma and dysentery).
According to a rather extensive USDA Forest Service web page entry, this is yet another plant that thrives in disturbed areas (can you say "ruderal?"), preferring damp locations along streams and ditches. This seems to be a common theme for most of the plants that I've found along the Masontown-to-Morgantown stretch of the rail trail.