Erigeron annuus (L.) Pers.

Erigeron annuus plant

Family - Asteraceae

Stems - To 1.5m tall, hirsute to sparse pubescent, simple or branching above, herbaceous, terete to ridged, from fibrous roots.

Erigeron annuus stemLower portion of stem.

Leaves - Alternate. Lowest leaves petiolate, to +10cm long. Petioles winged, to +2cm long. Upper cauline leaves sessile, non-clasping, lanceolate to linear-lanceolate, coarsely toothed to entire, with ciliate margins, pubescent above and below, to 9cm long, +2cm broad, reduced above.

Inflorescence - Single flower heads terminating axillary peduncles. Peduncles slightly expanded just below flower head, hollow, pubescent(appressed).

Involucre - In single subequal series or with outer series of tiny, scant bracts and single inner series. Phyllaries -1mm broad, 5-6mm long, entire, short pubescent to pilose, attenuate. Receptacle dome-shaped in cross section.

Erigeron annuus involucreInvolucre.

Ray flowers - Pistillate. Ligules white to pinkish, linear, threadlike, +/-100, to 1cm long, -1mm broad, glabrous.

Disk flowers - Disk to -1cm broad. Corollas yellow, 2-3mm long, 5-lobed. Achenes pubescent. Pappus of barbed capillary bristles to 2mm long and often with short outer row of scales.

Erigeron annuus flower

Flowering - April - November.

Habitat - Waste ground, pastures, prairies, disturbed sites, roadsides, railroads.

Origin - Native to U.S.

Other info. - This is one of the most weedy flowers in Missouri. It can bloom at a height of 10cm if mowed over or cut. The leaves have quite a bit of variation in the amount of teeth on the margins and the overall shape.

Photographs taken in the Ozark Scenic Riverways, 6-3-03.


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