My favorite medicinal herb! Also good for nutritious greens (cooked only!) when young and wonderful fibers when dry. Great for science lessons in the garden. Look for its brittle hairs filled with stinging chemicals. Cool stuff. FataMorgana

I'm certainly no expert, but I know you can get a clue if you look at the shape of the stem between where the roots begin up to where the leaves branch out. If it feels triangular or some other shape that helps to narrow it down. You can find information for weed ID on sites like: http://weeds.cropsci.illinois.edu/weedid.htm I think it is a slow day in the forum. I'm sure you'll get some good replies tomorrow.

Yes, that looks like it and would make a lot of sense, so it's almost definitely that. From what I understand this should be ok considering what the owner wants. I've already offered to enhance the turf, and even though I'm paid well, he simply doesn't want to at this point. Japanese Stilt Grass sounds like it should be able to handle mowing

Tansy? Cardamine impatiens? Descurainia? Let one flower and post the picture. Is it aromatic if you crush it? Where are you geographically?