Bittersweet Nightshade
This little guy supports itself by tangling into nearby plants. It's a vine, and a relative of potato, tomato, eggplant, and tobacco. The name comes from the taste of the stems, which are bitter at first, and then sweet. However, they are also pretty toxic (unless you're a bird), so I suggest you take my word for it...
They're often confused with deadly nightshade, which is a very toxic plant, but much less common in North America. I often worry that I will mis-categorize a plant in the field, and take a specimen home to paint it, and then one of my two cats will take a nibble, so painting this one gave me a little anxiety, despite my care at keeping it away from them, and the unlikeliness of having confused it with it's deadly doppelgänger.
When I think of nightshade, I think of Tim Burton's Nightmare Before Christmas, and the potion Sally makes for her mad scientist captor-creator in order to escape his tower. I think there's something sinister and delightfully eerie about finding an innocuous little vine like this at the roadside, admiring it for the translucency of it's fruit, and then getting the chills when learning more about it. Perhaps this would have been a better post around halloween.
Today is about the loveliest springtime day you can imagine here in Pittsburgh. Birds are chirping. The sun is bright, and the sky is blue. Yet, here I am, thinking about nightshade. Perhaps that urge to think about contrast, or the opposite of what you see, is what Robert Frost meant when he wrote, 'Spring is the mischief in me' in his poem, The Mending Wall. There's something about a gorgeous springtime day that makes me feel awfully reflective.