Valerianella radiata (L.) Dufr.
Family - Valerianaceae
Stems - To +50cm tall (typically shorter), herbaceous, angled (the angles minutely winged), hollow, with retrorse pubescence on wing margins, dichotomously branching, erect to ascending.
Leaves - Opposite, sessile. Lowest leaves spatulate, to +/-15cm long. Upper leaves reduced, becoming lanceolate-ovate, coarsely toothed below the middle, clasping. All leaves ciliate-margined (short), glabrous above, with pubescence on midrib below.
Inflorescence - Terminal dychasia, subtended by small lanceolate-ovate to lance-linear bracts. Flowers sessile. Bracts ciliate-margined.
Flowers - Corolla white, funnelform, 5-lobed. Corolla tube to 1.1mm long. Lobes rounded. Stamens typically 3, opposite corolla lobes, exserted, white. Style white, glabrous, exserted, 3-lobed. Ovary inferior, 3-locular, glabrous in flower. Capsule pubescent, to +/-2mm long. Locules (cells) of capsule asymetrical in cross section. The fertile cell broad and compressed. The sterile cells round and together equaling the width of the fertile cell.
My somewhat lame attempt at a graphic of the capsule in cross section showing the fertile and sterile cell orientation and relative shape.
Flowering - April - May.
Habitat - Prairies, pastures, wet meadows, valleys, creek beds, glades, roadsides, railroads.
Origin - Native to U.S.
Other info. - This is a very common plant throughout most of Missouri except the extreme northern portion of the state.
Photographs taken in the Hercules Glade Wilderness, Mark Twain National Forest, Taney County, MO., 4-28-00.