Stylophorum diphyllum (Michx.) Nutt.

Stylophorum diphyllum plant

Family - Papaveraceae

Stems - From a woody caudex and thick roots, to +/-40cm tall, erect to ascending, herbaceous, fistulose, mostly green but purple at the base, glaucous, sparse to moderately pilose. Trichomes of the plant multicellular.

Stylophorum diphyllum stemLower stem.

Leaves - Basal leaves long-petiolate, pinnatifid. Petioles to +/-16cm long, purplish near the base, green apically, with a shallow adaxial groove, sparse pilose. Blades pinnatifid. Divisions of the blade to +/-6cm long, +/-3cm broad, with rounded lobes, green and glabrous adaxially, heavily glaucous and sparse pilose abaxially. Rachis between the leaf divisions with pilose hairs.

Stylophorum diphyllum leafAdaxial surface of leaf.

Stylophorum diphyllum leafAbaxial leaf surface.

Inflorescence - Terminal umbel of 1-many flowers. Umbels subtended by a pair of opposite leaves. The leaves reduced. Pedicels of the umbels subtended by a pair of subulate bracts. Bracts to +1cm long, +/-3mm broad, pilose, acute. Pedicels to +6cm long, sparse pilose, glaucous, terete, erect.

Flowers - Petaloid sepals 4, spreading, distinct, yellow-orange, broadly obovate, to +/-3cm long and broad, glabrous. Petals absent. Stamens many, erect, from below the pistil. Filaments yellow, to 7mm long, glabrous. Anthers yellow, +2mm long, +1mm broad, compressed. Ovary superior, 6-10mm long in flower, 3-4mm in diameter, narrowly ovoid, densely antrorse strigose, yellow-green, unilocular, with many ovules. Placentation parietal. Style yellow-green, glabrous, 2-3mm long. Stigma with a truncate apex, 2-4-lobed. Fruits pendant, to +2cm long, dehiscing by 4 valves. Seeds with a distinctive keel of white pubescence and otherwise shiny and dark brown to black.

Stylophorum diphyllum flowerFlower close-up.

Stylophorum diphyllum fruitFruit.

Stylophorum diphyllum plantFruiting plant.

Flowering - April - June.

Habitat - Rich soils of woodlands, base of bluffs, along streams, ravine bottoms.

Origin - Native to U.S.

Other info. - This striking plant can be found in the east-central portion of the state and in a few southwestern counties. It is simple to identify because of its paired leaves, brilliant yellow flowers, and bristly fruits. The species is also cultivated and grows well in many conditions.

Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 5-12-03, and in Columbia, MO., 4-15-04.


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