Floerkea proserpinacoides Willd.
Family - Limnanthaceae
Habit - Annual forb.
Stems - Spreading or loosely ascending, to 30 cm, glabrous.
Stem and node.
Leaves - Alternate, short to long petiolate. Stipules absent. Blades 2-7 cm long, pinnately deeply divided to once-compound with 3-7 leaflets, these 0.4-2.0 cm long, narrowly elliptic to oblanceolate, the margins entire.
Inflorescences - Solitary axial flowers.
Flowers - Perfect, hypogynous, long-stalked. Calyces of 3 free sepals, these 2.5-3.0 mm long at flowering, becoming enlarged to 6 mm at fruiting, lanceolate to narrowly ovate, narrowed to a sharply pointed tip. Corollas actinomorphic, of 3 free petals, these 1-2 mm long, oblanceolate, white. Stamens 3-6, free, the anthers yellow. Pistil of 2 or 3 carpels, these free nearly to the base. Ovaries superior, each with 1 locule containing 1 ovule. Style 1, attached toward the carpel base in the depression between the ovaries, the stigma 2-lobed.
With penny for scale.
Fruits - Schizocarps breaking apart into achene-like mericarps, these 2.2-2.6 mm long, broadly ovoid to nearly globose, somewhat fleshy, the surface green, finely warty.
Flowering - April - May.
Habitat - Bottomland forests.
Origin - Native to the U.S.
Lookalikes - None close.
Other info. - This tiny species is rarely seen. Not only are the flowers minute and inconspicuous, but the species is uncommon in Missouri, reported so far from only 8 counties in the east-central part of the state. The U.S. distribution comprises two widely disjunct populations, one in the northwest and one in the northeast, both extending into Canada. Once discovered, the plant is relatively easy to identify, having no close lookalikes. In Missouri this plant is the sole member of both its genus and family which grows naturally in the state. Floerkea proserpinacoides is intolerant of disturbance and has a conservatism coefficient of 10.
Photographs taken at Cuivre River State Park, Lincoln County, MO, 4-2-2012 (SRTurner).