Scentless chamomile
(Tripleurospermum perforatum)

An annual, biennial or short-lived perennial forb introduced from Europe that reproduces by seed. Stems can grow 3 to 6 feet tall. The flowers on scentless chamomile are daisy-like, with one yellow, centered flower and white petals for every stem. Leaves are alternate, finely divided, resemble a fern and odorless when crushed.
Most commonly found in moist areas such as pastures, stream banks, fence lines and drainages. Scentless chamomile can be devastating to livestock by causing blistering on muzzles and irritation to mucous membranes. It is rare, but may be found throughout Garfield County in small numbers.