Galinsoga parvilflora - and its flora are very parvi. Tiny flowers. Like small white and yellow daisies. You probably know the one.
Yes, you can eat it. Raw, it tastes like pea greens, slightly sweet. Cooked - spinachy, chardy, collardy.
The Galinosoga story is an odd one. I had sown an entire packet of Magenta Spreen lamb's quarters, from Johnny's Seeds, in two troughs. What came up? Galinsoga. It may be some fluke, or accident, or coincidence - the seeds I sowed were tiny and black. And I have no lamb's quarters... Certainly I have noticed Galinsoga in the past (though I had no name for it, then) - but as far as I know it did not set seed. I always yanked it out.
And late summer is peak weed season. Peakweed. Pigweed.
(Joke. Worse, pun. Sorry.)
Pigweed is the sloppy-looking green species of Amaranth that most people would not look at twice. Amaranthus retroflexus and A. hybridus, practically invisible, it is so ubiquitous. It has a handful of common names. As I have written before, it is nutritious and earthy, and I prefer the leaves' mouthfeel to spinach, which isn't in season in hot weather, anyway. Think of it as summer spinach, now that high summer has turned a corner and is beginning the freefall to September, with Glut at its heels.
Last night I picked two large bundles of each plant, stripped the leaves, wilted them, and added the just-cooked leaves to pine nuts, raw garlic, parmesan, butter, olive oil and, the key ingredient, lemon zest. (In the past weeks I have eaten up all the salt-preserved Meyer lemons of spring, so yesterday's green sauce contained the peeled zest of one fresh lemon. Yes, I made some more preserved lemons, too.)