Ratibida pinnata (Vent.) Barnh. - Gray Head Coneflower

Ratibida pinnata plant

Family - Asteraceae

Stems - To -2m tall, multiple from base, herbaceous, erect, branching above, hirsute, scabrous, carinate, from caudex.

Ratibida pinnata stem

Leaves - Alternate, sessile, pinnatifid to pinnately divided, +/-18cm long, scabrous, hirsute on midrib, with typically 3-11 lobes. Lobes entire to coarsely toothed, often divided again. Basal leaves drying before flowers.

Ratibida pinnata leaves

Inflorescence - Single flower heads from long(+/-20cm) naked peduncles.

Involucre - Phyllaries spreading to reflexed, +/-9mm long, 2mm broad, subulate, antrorse strigose, scabrous.

Ratibida pinnata involucre Involucre.

Ray flowers - Flowers typically 10 in number. Ligule yellow, +/-6cm long, to 1.5cm broad, pubescent below and less so above, notched at apex, spreading to reflexed. Flowers sterile. Achene 2.5mm long, pubescent at apex. Pappus absent.

Disk flowers - Disk to 1.5cm in diameter, 2cm long, subglobose. Flowers fertile. Corolla tube to 2mm long, glabrous, 5-lobed. Lobes .2mm long, acute, deep brownish-purple, spreading. Stamens 5. Anthers deep brownish-purple, connate around style. Pollen yellow. Style exserted, bifurcate. Stigma deep brownish-purple. Achene slightly flattened, 3mm long, white, glabrous. Pappus absent. Receptacle 1cm long, 3mm broad, cylindrical. Chaff with purple margins, white below, green at apex, 5mm long, partially surrounding achene.

Ratibida pinnata flowers

Flowering - May - September.

Habitat - Prairies, thickets, woodland edges, streambanks, railroads.

Origin - Native to U.S.

Other info. - This plant is common in the state and easy to ID in the field. The subglobose disk, long ray ligules, and pinnate leaves are good characteristics to look for.
I first photographed this plant by Buffalo Creek in Ripley County. Besides being a great place for plants, Buffalo Creek is loaded with crayfish:

Oronectes luteusOronectes luteus

Oronectes punctinamus Oronectes punctinamus

I had tons of fun snorkeling and catching these crayfish in the crystal clear waters of Buffalo Creek. As tempted as I was, I did not eat any for dinner that evening.

Plant photographs taken off Hwy H., Shannon County, MO., 7-3-03 and 6-25-04.


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