This plant is a weed, but I kinda like it. The whole plant is sticky (is that why it’s called catchfly?) and the small pinkish-white flowers are perched atop a vase-shaped calyx. The petals are fused together, with little toothlike projections sticking up like a fringe around the inner edge. There are distinctive stripes running perpendicularly along the calyx (which is all the sepals taken together). The whole thing is a nice bit of floral architecture – if you can forget that it’s an invasive that was introduced from Europe!
Also, Silene gallica is another member of the Caryophyllaceae (a.k.a pink, or carnation) family. So check for the swollen nodes where the opposite pairs of leafs join the stem that I talked about a few posts back!
You may wonder why I always talk about families – the reason is that whether you are keying or looking plants up in a guidebook, being able to confidently narrow your options down to one or two families makes the whole process a lot easier. It also helps train your eye and mind in the detailed way of looking at plants that is needed for good identification.