Perennial herb 30 cm - 1 m tall Leaves: numerous, alternate, stalkless, up to 8 cm long and 2 cm wide, lance-shaped or narrowly egg-shaped, non-toothed, hairy, and with obvious lateral veins. The basal leaves are smaller than the stem leaves, but they fall off early in the season. Inflorescence: of several, alternate, loosely spreading-hairy, somewhat arching, long, spike-like clusters at the top of the stem, with each short-stalked flower subtended by a bract. Flowers: numerous, dull white with greenish tips, 1.1 - 2 cm tall, more or less radially symmetric, funnel-shaped with narrow basal tube then widened above and ending in shorter ascending petal lobes. Sepals: five, very narrow, linear, 0.8 - 1.2 cm long (much shorter than petal tube), and loosely spreading-hairy. Petals: hairy, five, but fused for most of their length (over twice the sepal length) into a narrow dull white tube for about half the length, then the tube widening to more funnel-shaped before finally separating into five, ascending to slightly flared, greenish, somewhat lance-shaped, abruptly but distinctly pointed lobes. Stamens: five, attached to top of petal tube, with 1.5 - 3.5 mm long anthers, but not extending beyond petal tube. Pistil: with one, four-lobed, superior ovary; and a single, very long, slender, threadlike style which is greatly exserted beyond the petal tube and lobes. Fruit: usually one or two, but up to a cluster of four, 4 - 5 mm tall, erect, egg-shaped, shiny, smooth, bony nutlets with a rounded base. Root: stout and woody. Stems: several, green, and covered with 1 - 2 mm long, loosely appressed or ascending hairs.
Similar species: Onosmodium bejariense var. occidentale is most similar to O. bejariense var. hispidissimum, except that variety is typically larger with leaves between 8 and 15 cm long and 1.5 - 4 cm wide, its flowers are shorter (only up to 1 cm ) with much shorter and wider petal tubes (about equal length to sepals), and its nutlets are dull, brownish tinged, smaller (up to 3 mm tall), and have a basal collar or constriction. Also similar is the typical variety O. bejariense var. bejariense, which is south of our area and can be distinguished by its smaller size, the covering of appressed hairs which give the plant an ashy-white color, the more uniformly thickened petal tube, and the nutlets are dull and pitted. Onosmodium bejariense var. occidentale is also very similar to O. virginianum, which exists east of the Chicago Region, except that species has yellow petal lobes.
Flowering: May to July
Habitat and ecology: Incredibly rare, only collected once from a locale where it is unclear if the specimen was cultivated or natural, and the specimen even shares many characteristics with O. bejariense var. hispidissimum.
Notes: This taxon ranges in the plains and prairie regions of central North America in mostly silty-clay or sandy soils, so it would not necessarily be unexpected if found in the very western areas of the Chicago Region. This used to be placed under the species name Onosmodium molle as O. molle var. occidentale, however Turner (1995) aligned this with a Texan species, O. bejariense, based on the intergradation between the taxa. The name Onosmodium molle became obsolete.