Field Guide

The flowers of dayflower are truly blue, and they have only two conspicuous petals. A fast-growing, sprawling, but shallow-rooted weed, this introduced species commonly annoys gardeners.

Three species of yucca grow wild in Missouri. Spanish bayonet was introduced from the Southwest and has escaped from cultivation, but our two soapweeds are native.

White crownbeard is a tall native perennial wildflower with clusters of white flowerheads. It's called “wingstem” for the narrow green wings running along the stem. It’s called “frostweed” because it forms "frost flowers": strange and beautiful formations at the stem bases after a sudden hard frost.

Compass plant grows to 8 feet tall and has foot-long, deeply cleft leaves at its base. It got its common name because its leaves turn so that the surfaces face east and west to take full advantage of the sun’s rays.

Called carpenter’s weed for its remarkably square stems, cup plant is also notable for its large, opposite leaves that fuse around the stem to form a leafy cup that holds rainwater.

Of Missouri’s six rosinweeds, prairie dock is identified by its large, leathery, unlobed leaves, which are nearly all in a basal whorl. Only a few small leaves grow on the stem.

“Infestation” is the term for what teasels are doing in Missouri. Learn to identify these thistlelike plants, and help to control the weedy spread of these tough, prickly invaders.

Large stands of wind-pollinated giant ragweed commonly form in disturbed areas, causing late-summer misery in the form of hay fever for many Missourians.

Tickseed sunflower has flattened black seeds that attach themselves to clothing and pets via two needlelike awns. In flower, it grows in massive displays in moist bottomlands.

Narrow-leaved vervain is a short, slender perennial with single stems or with upper stems sparingly branched. Its many small flowers are crowded on narrow spikes. The corollas are tubular, deep lavender or purple, with 5 spreading lobes.