How wet is the surrounding ground? I've had a lot of rain in my area recently and the ground has become saturated. As a result, I've started seeing a lot of gnats around my plants and they have developed a slightly yellowish/wilting look to them. Some research indicates that I might have fungus gnats. The larva harm the roots of young seedlings, causing a wilted look and the increased moisture could lead to a fungal problem. I'm no expert (first time gardener) but you might want to check your moisture levels and look up fungus gnats. Jeremie.

Thanks for plugging my site. Yes, that is the wild radish Raphanus raphanistrum that is blossoming now. Edible from top to bottom. The key difference between a mustard and a radish is the radish will have noticeable veins in the flower petals and the flowers will be on individual stems. Wild mustard blossom petals don't have obvious veins and they cluster. Also, mustards have a a smooth seed pod (on a peduncle) and radishes have a rippled seed pod (on a peduncle.)

Here's a site that may help: http://en.wikipedia.org/wiki/Brassicaceae The flowering plant family Brassicaceae, also called Cruciferae, is known as the mustard family or cabbage family. The family contains species of great economic importance, providing much of the world's winter vegetables. These include cabbage, broccoli, cauliflower, brussels sprouts, collards, and kale (all cultivars of one species, Brassica oleracea), Chinese kale, rutabaga (also known as Swedish turnips or swedes), seakale, turnip, radish and kohl rabi. Other well known members of the Brassicaceae include rapeseed (canola and others), mustard, horseradish, wasabi and watercress. Brassica oleracea, a plant of Atlantic Europe and the Mediterranean, is the precursor to Cabbage, Brussels Sprouts, Broccoli, Kohlrabi, Cauliflower, Kale, and most recently Broccoflower, a hybrid of Broccoli and Cauliflower. Radishes range in sizes, in some instances growing to proportions of over 1 kg (2 lb). The East Asian giant white radish is called "Chinese radish" or "daikon". It is mild-flavored and is usually called daikon radish in US supermarkets. The most common variety is carrot-shaped, and approximately 8 to 14 inches (20 to 35 cm) long and 2 to 4 inches (5 to 10 cm) in diameter.

Right genus, but not turnip. Try Brassica nigra or one of the other mustards. The one with the white/pink flower might be wild radish, Raphanus raphanistrum. FataMorgana