''Thaspium trifoliatum'', commonly called meadow-parsnip
[ or purple meadow-parsnip][ It has a broad natural habitat, which includes mesic to dry forests and woodlands, prairies, bluffs, and rock outcrops.][
]
Description
''Thaspium trifoliatum'' is an herbaceous perennial growing tall. It has a few basal leaves
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...
that are about across and heart-shaped. Stem leaves are alternate and trifoliate, with 3 lanceolate to ovate-lanceolate leaflets measuring long.[ The leaflets are finely serrate with a notably white-translucent margin.][
The inflorescence is a compound, flat umbel with very small flowers at the end of the upper stems. The flower at the center of the umbel is slightly higher than the others.][
The yellow-flowered variety of ''Thaspium trifoliatum'' bears a striking resemblance to '']Zizia aptera
''Zizia aptera'' is a flowering plant native to North America. Its common names include meadow zizia, golden alexanders, heart leaved golden alexanders, and prairie golden alexanders.
Description
The leaves are long, ovate and indented at the ...
'', with which it is frequently misidentified when not in fruit.[ ''Thaspium trifoliatum'' can be distinguished by its glabrous stem internodes (as opposed to minutely puberulent), and pedicelled central umbellet flower (as opposed to sessile).][ Maroon-flowered populations are more easily recognized as ''Zizia aptera'' is strictly yellow.
]
Taxonomy
Two varieties have often been recognized. However, some botanists have expressed uncertainty on which characters should be used to distinguish them, or even if they should be taxonomically recognized at all.[ The most widely used differentiation is based on solely flower color:
* ''Thaspium trifoliatum'' var. ''aureum'' Flowers yellow. Widespread throughout much of eastern North America.
* ''Thaspium trifoliatum'' var. ''trifoliatum'' Flowers maroon. Found primarily from the Appalachian Mountains eastward, with disjunct populations westward in the Ozark Mountains.
]
Ecology
''T. trifoliatum'' is a food source for caterpillars of the black swallowtail (''Papilio polyxenes
''Papilio polyxenes'', the (eastern) black swallowtail, American swallowtail or parsnip swallowtail, is a butterfly found throughout much of North America. It is the state butterfly of Oklahoma and New Jersey. An extremely similar-appearing spec ...
'') and Ozark swallowtail (''Papilio joanae
''Papilio joanae'', the Ozark swallowtail, is a North American butterfly species in the family Papilionidae.Jim P. Brock and Kenn Kaufman (2003). ''Butterflies of North America.'' Houghton Mifflin, New York, NY. It was once considered a synonym ...
'') butterflies.
References
{{Taxonbar, from=Q15597571
Apioideae