Field Guide

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.

Next time you breeze past weedy black mustard on the highway or spot it in a fallow field, think of how important this and other mustards are to the world economy – and to your dinner table.

A spiny annual with bright yellow flowers and dandelion-like leaves, buffalo bur is an introduced member of the nightshade family.

Wood nettle, or stinging nettle, often forms dense stands in bottomland forests, streamsides, and other places. There, canoeists, anglers, and others try to avoid touching its stinging hairs!

Pretty but poisonous, jimsonweed has white goblet-shaped flowers that open around midnight. This native of tropical America was introduced nearly throughout the United States and thrives in disturbed soils.

A biennial plant with bristly hairs and usually with single stems, viper’s bugloss can grow 2½ feet tall. The flowers are pink in bud, blue to ultramarine later. The protruding stamens are pink.