Collomia linearis Nutt.
Family - Polemoniaceae
Stem - Erect, to 60 cm, pubescent with fine hairs especially toward tip.
Leaves - Alternate, simple, entire, sessile, with single midvein. Lower leaves linear to lanceolate. Upper stem leaves lanceolate to ovate, pointed at tip, bases somewhat clasping. Abaxial surface with short, often glandular hairs along midvein.
Stem and leaves.
Inflorescences - Terminal and axillary, headlike clusters surrounded by leafy bracts.
Calyx - 5-lobed to about midpoint, 4-7 mm long at flowering, elongating at fruiting, narrowly bell-shaped. Calyx lobes triangular, glandular-hairy.
Corolla - 5-lobed, white to pink, trumpet-shaped. Tube 8-15 mm long, lobes 1-4 mm long. Stamens unequal. Anthers mostly included.
Flowering - May - August.
Habitat - Pastures, open disturbed areas.
Origin - Native to the western U.S.
Other info. - This inconspicuous sibling to the phloxes is very rare in Missouri, possibly no longer occurring in the state at all. The plant is only known in Missouri from a single historical collection, in Marion County in 1918. It can be easily recognized by its tubular phlox-like flowers, alternate leaves, and generally diminutive appearance.
Photographs taken along the Little Muddy Creek, southwest of Bear Mountain, CO, 6-26-2018 (SRTurner).