Much-branched, upright perennial, without hairs. Flowers minute, in compound, flat umbels, dark yellow, rarely purple or brownish purple. The central floret of each umbellet is slightly raised, on a stalk. Blooms April–June. Basal leaves simple, heart-shaped or only once-divided. Stem leaves on long stems (petioles) divided into 3 pointed, egg-shaped, finely toothed leaflets with a rounded base. All leaflets have a very narrow yellowish-white margin, a ready identification characteristic.
Similar species: Our other meadow parsnip species, T. barbinode, lacks the pale borders of the leaves. Golden Alexanders (Zizia spp.) are similar, but they don’t have the middle flower in each umbel slightly raised; instead, that floret is mostly stalkless and recessed. A surer way to distinguish between these genera is to examine the fruits: Those of Thaspium are strongly winged, while those of Zizia are unwinged or only ribbed or slightly winged.
Height: to 2½ feet.
Scattered nearly statewide, but more common south of the Missouri River.
Habitat and Conservation
Grows in mesic to dry upland forests, upland prairies, savannas, glades, ledges and tops of bluffs, and less commonly banks of streams; also old fields, roadsides, and railroads.
Two varieties of meadow parsnip are found in Missouri, with the only difference being the flower color. Thaspium trifoliatum var. flavum, yellow meadow parsnip, has yellow flowers. It is scattered nearly statewide, though more common south of the Missouri River. Var. trifoliatum, purple meadow parsnip, has maroon or purplish flowers. It is uncommon and widely scattered in the Ozark section.
Distinguishing, with certainty, between this plant and the similar-looking golden Alexanders is a bit of a challenge. But people love challenges. Indeed, it is part of our human nature, and being able to identify plants, with certainty, was once a matter of survival.
Bees, butterflies, flies, and other insects collect nectar and pollen from the flowers. Black swallowtails and Missouri woodland (or Ozark) swallowtails use this and other wild carrot-family species as natural food plants for their larvae.