General: Celery Family (Apiaceae). Daucus pusillus is a native annual found most commonly during the early-mid part of the growing season. In most parts of Texas, this species has gone to seed by mid-summer. Rattlesnake-weed resemble their cultivated relative, the garden carrot. The stem is normally slender, from 2-4 feet in height and unbranched or only a single weak branch as compared to the introduced Daucus carota, which is sometimes heavily branched and more robust. The flower is a white umbel. Upon maturity, the flower cluster (umbel) closes to form a cup or bird’s nest. The leaves are pinnately compound and finely cut. Leaflets are deeply serrated (saw-toothed). The seed of Daucus carota have fine hairs rather than the stiff bristles common to Daucus pusillus. Another distinguishing characteristic between the two species is the central flower of each individual umbellet is rose or purple in Daucus carota rather than being white throughout as found in Daucus pusillus.

American wild carrot is self-fertile. The flowers are hermaphrodite, having both male and female organs, and are pollinated by flies and bees.

A similar species is water parsnip (Sium suave), which has a corrugated main stem and leaves only once compound. Bishop’s weed (Ammi majus) and water hemlock (Cicuta maculata) have white umbels, but the leaflets are not deeply serrated or carrot like.

Rattlesnakeweed, southwestern carrot, seedticks, rattlesnake-weed, yerba del vibora

Canada

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Daucus (pusillus or carota) is likely the most common and widespread plant with white umbels growing along Texas’ roadsides. It is known from the U.S. West Coast and the southern half of the U.S. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Daucus pusillus Michx.:
Brazil (South America)
Canada (North America)
Chile (South America)
United States (North America)

Adaptation: It is very common along road right-of-ways. It can also become quite dominant in some pastures and prairies. Rattlesnake weed prefers moist, loamy sites, but not wet sites. The exotic, Daucus carota, tolerates a much broader site in Texas, ranging from blackland to rock outcrops.

American wild carrot requires moist, well-drained soil and prefers sandy, loamy and clay soils. It grows best in a sunny position and cannot tolerate shade. This species occurs in rocky prairies, openings in woodland, and rocky open, frequently limestone, glades, and edges of bluff escarpments, sometimes along roadsides and railroads (Steyermark 1963).

Propagation by Seed: American wild carrot seeds are best sown in the autumn. Always aim to sow thinly and evenly to permit adequate room for the seedlings to grow and develop freely (Heuser 1997). The seeds will germinate better if they are cold stratified.

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G5 - Secure

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).

These plant materials are readily available from commercial sources. Contact your local Natural Resources Conservation Service (formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government.” The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”

Comments: North American Indians used this species as a talisman in gambling, roots for food purposes, and as a remedy for snakebites.

Ethnobotanic: Native Americans ate the roots raw and cooked (Epple 1995).

Medicinal: In California this species is called rattlesnake weed, because the herbage is reputed to be efficacious in the treatment of snakebites (Moldenke 1949). A poultice of the chewed plant has been applied to snakebites (Moerman 1998). A decoction has been used to treat colds, itches and fevers (Ibid.).