PlantFiles: American wild carrot
Daucus pusillus

American wild carrot (Daucus pusillus) is also known as rattlesnake weed and southwestern Carrot and is a plant that grows natively in many states. It is considered a noxious weed by many.

In Texas, it can be found growing in the South Texas Plains and the Edwards Plateau regions on barrens, meadows, plains, dry hills, roadsides, streambanks and waste areas. It is not picky about soil types. Simple to few-branched and erect, it grows 2 to 3 feet tall and its roots have a characteristic carrot odor. The leaves are fern-like and lacy (alternate, pinnate and compound). The stems are retrorsely-hispid (covered in rigid or bristly hairs that are directed back or downwards). The leaves are eaten by white-tailed deer.

It blooms March or April through June/July. The flat to cupped, 1 1/4 to 2 inch wide flowerhead is composed of several tiny, white, 5-petalled, 5-staminated flowers gathered in a compound umbel. They do not have a red or purplish central flower that is characteristic of Queen Ann's lace (Daucus carota). The flowers are hermaphrodite (have both male and female organs) and is self-fertile; however, they are pollinated by beetles and flies as well. The flowers are subtended by sturdy, lacy bracts (modified leaves) which support them (and later the fruit). The bracts may be longer than the flower cluster is wide. The flowers are not long lasting and begin turning into fruit quite quickly. The oblong fruit (seed pods) each have two rows of stiff bristles.

The root is edible either raw or cooked (see caution below). The plant is thought to be an antipruritic and blood purifier. It has been used to treat colds, itches and fevers. It obtained the common name "rattle snake weed" because a poultice of the chewed plant has been used to treat to snakebites. Recent studies have indicated that it may be a cancer preventative.

Cautions:
If the sap contacts the skin of some people, dermatitis and/or photo-sensitivity can occur. The taproot and the leaves are easily confused with poison hemlock (conium maculatum which is one of the most deadly poisonous wild flowering plants. I would be very careful about eating wild carrot as food.

Basically a roadside weed for this part of the world. The flowers are interesting to watch open, but in a garden setting it will seed itself everywhere and the long taproot make it hard to pull out.