Helenium flexuosum Raf.

Helenium flexuosum plant

Family - Asteraceae

Stems - To 1m tall, erect, typically single from base, from fibrous roots, branching above, herbaceous, heavily winged from decurrent leaf tissue, scabrous, strigose. Wings of stem to 5mm broad.

Helenium flexuosum stem

Leaves - Basal leaves lanceolate to elliptic, to +20cm long, scabrous, strigose, entire to lobed. Cauline leaves alternate, lanceolate, acute, entire or with few shallow teeth, scabrous, densely strigose, to +10cm long, -2cm broad, reduced above, with heavily decurrent tissue from base.

Inflorescence - Flower heads in loose corymbiform cluster at apex of stems. Peduncles carinate, densely strigose, scabrous.

Involucre - Phyllaries linear, attenuate, reflexed at maturity and curling, in one series, 1-1.4cm long, 2.1mm broad, strigose abaxially and on margins, glabrous adaxially.

Helenium flexuosum involucreInvolucre.

Ray flowers - Ligules yellow, to 2.5cm long, -2cm broad, 5-lobed at apex, tapering to base, densely pubescent below, glabrous above. Flowers sterile. Achenes flattened, short pubescent. Pappus of awn- tipped scales.

Disk flowers - Disk to 1.5cm broad and tall, domed to globose. Receptacle ovoid. Corolla tube of disk flowers yellow, 2-3mm long, 4-lobed, dark maroon at apex because of dense glandular pubescence. Styles bifurcate, yellow. Flowers fertile. Achenes pubescent, 1.2mm long in flower. Pappus of 5-6 awn-tipped scales.

Helenium flexuosum flower

Flowering - June - November.

Habitat - Pond margins, streambanks, ditches, swamps, wet meadows, wet depressions of prairies, pastures, moist areas of glades.

Origin - Native to U.S.

Other info. - H. flexuosum and other species in the genus contain a lactone known as Helenalin. This compound is poisonous to various animals but has anti-cancer properties. This species is often found standing alone in pastures as cows will not eat it. The plant is quite striking when in full flower and I think it should be cultivated more. It's a great plant to grow in those difficult wet areas of a yard.
H. felxuosum is easy to ID in the field because of the heavily winged stems and brown disk flowers.

Photographs taken at Bethel Prairie, Barton County, MO., 7-4-03.


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