Pediomelum esculentum (Pursh) Rydb.

Prairie Turnip

Pediomelum esculentum plant

Family - Fabaceae/Faboideae

Habit - Perennial with turnip-shaped, tuberous-thickened taproot.

Stems - 1-3, to 30 cm, erect, densely pubescent with long, spreading hairs.

Pediomelum_esculentum_stem.jpgStem.

Leaves - Alternate, stipulate, long-petiolate, palmately compound. Stipules 12-18 mm long, lanceolate, hairy. Blades mostly 5-foliate, the leaflets entire, to 5 cm, lanceolate to oblanceolate, with hairy margins, the upper surface glabrous except along the midvein, the lower surface densely pubescent long appressed hairs.

Pediomelum_esculentum_leaves.jpgLeaves.

Pediomelum_esculentum_leaf2.jpgLeaf abaxial.

Inflorescences - Dense spikelike racemes, to 6 cm long and 0.8-2.5 cm wide, elongating slightly with age, the stalk 7-11 cm long, the bracts 9-15 mm long, broadly lanceolate to ovate, tapered at the tip, hairy, the flower stalks 1-3 mm long.

Pediomelum_esculentum_inflorescence.jpgInflorescence.

Flowers - Calyces long-hairy, the tube 4-5 mm long, somewhat pouched at the base, the upper lobes 4-7 mm long, the lowermost lobe 7-10 mm long. Corollas papilionaceous, 14-18 mm long, lavender to purple or light bluish purple, often bleaching to tan with maturity, the banner sometimes with a darker midnerve and the keel dark purple at the tip. Stamens 10, with 9 of the filaments fused, the fused portion 10-11 mm long, the free portion 1-3 mm long.

Pediomelum_esculentum_calyces.jpgCalyces (top view).

Pediomelum_esculentum_calyces2.jpgCalyces and bract.

Pediomelum_esculentum_flowers.jpgFlowers.

Fruits - Modified legumes, to 6 mm long, oblong, glabrous, sessile, abruptly tapered to a curved hairy beak, the surfaces papery, 1-seeded. Seeds 4-5 mm long, olive green to reddish brown, sometimes with darker streaks or mottling, smooth, somewhat shiny.

Flowering - April - July.

Habitat - Glades, upland prairies, bluff tops.

Origin - Native to the U.S.

Other info. - This plant is fairly uncommon in Missouri. The main part of its natural range extends in a band northwestward from Missouri through much of Montana. The plant is easily recognized by its 5-foliate leaves, extreme hairiness, and large inflorescences. It is highly conservative, with a conservatism rank of 10.

The large, starchy root is nutritious and was used as a food source by Native American peoples of the Great Plains. It was also consumed by early French explorerers, who called it pomme de prairie (apple of the prairie). The specific epithet esculentum means "edible" in the sense of being fit for human consumption.

Photographs taken at Valley View Glade Natural Area, Jefferson County, MO, 5-30-2009, 5-24-2014, and 5-8-2017 (SRTurner).



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