In addition to Lamb’s Quarters (wild amaranth) and some Relative of Dandelion, I’ve got a further unidentified, windborn plant growing in with my cucumbers and nasturtium.
It has white flowers, a bit like tomato flowers, and round fruits that look like very, very tiny tomatoes. It also has leaves that look a bit like a small version of the leaves of an eggplant.
So I’m pretty sure that this is a nightshade family plant.
So I looked it up using Google Images.
European Black Nightshade.
It might also be Hoe/Harry Nightshade. Not sure.
It’s not Woody Nightshade (which is a vine with tomato-like, purple flowers), and it’s not Deadly Nightshade (Atropa Belladonna) – which has bell-like, purple flowers, and leaves that are more like those of a hot pepper plant. (It’s also bigger than the stuff growing in my garden, by the sounds of things, but I don’t know that for sure).
I gather (er, from the internet) that Solanum Nigrum is a sedative, anti-convulsive, and anti-cancerous drug. Topically, the juice of the leaves can be used to help get rid of shingles (adult-chicken-pox) and other skin problems.
The stuff that makes nightshades toxic is… unevenly distributed through the leaves, berries, flowers, and roots of Solanum Nigrum, so it’s hard to be really sure what kind of a dose you’re getting. So possibly, if you’re using this for medical purposes, doing so toppically is a better way to go.
Magically speaking, you could carry the dried herb on your person, or place it under your pillow, to help you get over an ex-sweetheart. You could also hang it (hidden) around your house to protect it from general nastiness, rotten intentions, and people who mean you no good. It can (I think) technically cause vertigo and delirium but it ain’t got nothin’ on its cousins, so use something else if you want to experiment with flying ointment.
Solanum Nigrum, like other nightshades, can be used in spells concerning Glamoury and also in rituals pertaining to, or honouring, the dead.
Meliad the Birch Maiden. 🙂
 That said, you can aparently boil the hell out of the leaves and eat them like spinach. None the less, I’m inclined to treat this the way I treat Motherwort: You can technically put it in your mouth but… only under specific circumstances and don’t treat it like food.