Good fodder, also for bees. The greens can be used as spinach.
Carrots are also a surprisingly large family. The most common, the commercial orange carrot, is an example of the earliest commercialisation of a hybrid for fashionable purposes. It was, apparently, developed to honour the Prince of Orange. Cute myth. Wild or overgrown carrots are recognised by the rather large flat umbrellas of white flowers. This umbrella dries into a fist of spikes holding many burr-like seeds.
Though the root is the most commonly sought part, the leaves are quite useful too. The seeds are easily plucked off a dried stem. It takes some experience to judge the best moment to remove a carrot from the ground. In general, once the flower shows the tiniest trace of forming, the root is already old and stringy.
Carrots can be kept fresh quite long by hanging them in small bunches in the dry shade. As long as air can move around each individual carrot, it should not rot or go mouldy. The leaves can be dried as winter fodder. The flowers are hard and dry, and last long in a paper bag. Crushing the seeds with a bottle helps when drawing for tea.
The seeds are the medicine here; it helps with severe flatulence and burping. Be warned, though; it is likely to come out all in one big bang before you quickly feel better. Colic falls into this category.