Family - Primulaceae

Stems - To +/-30cm tall, branching, decumbent, repent, or erect, herbaceous, 4-angled, glabrous to pubescent, sometimes rooting at the nodes.

Leaves - Opposite, entire, sessile, ovate, to 2cm long, 1.3cm broad, clasping or not, with brown speckles below, variously pubescent, margins somewhat tuberculate.

Inflorescence - Single flowers from leaf axils. Peduncles to 1.4cm long, glabrous.

Flowers - Corolla orange-red, rarely bluish, to -1cm wide, rotate. Petals 5, united at base and forming very short tube, 4mm long, 3-3.5mm broad, broadly ovate, broadly elliptic, or orbicular. Stamens 5, adnate at base of petals. Filaments purple, 2mm long, pubescent with purple multicellular hairs. Anthers yellow, .5mm long. Style single. Calyx with very short tube(-1mm long), 5-lobed. Lobes lanceolate, 4mm long, with scarious margins, keeled at midvein.

Fruit.

Flowering - May - September.

Habitat - Roadsides, pastures, waste ground, disturbed sites. Typically in moist soil.

Origin - Native to Eurasia.

Other info. - This small species can be found mainly in the southern half of Missouri. The plant is easy tp identify becasue of its sessile, opposite leaves, orange-red flowers, and globose fruits. The fruits of this species are globose, circumscissile capsules which contain many tiny seeds.
Steyermark lists two forms for the state. Form arvensis, shown above, has a red-orange corolla, and form caerulea has a blue corolla. The latter form is much less common but much more striking in my opinion.
If untouched, the plant can form mats, since it sometimes roots at the nodes.

Photographs taken off Highway 64, outside of St, Louis, MO., 8-7-05.