Carduus nutans L.

Carduus nutans plant

Family - Asteraceae

Stems - To +2m tall, herbaceous, erect, glabrous to arachnoid pubescent, from taproot, often branching, winged(from extended leaf bases). Wings with spiny margins.

Carduus nutans stemUpper stem.

Carduus nutans stemLower stem.

Leaves - Basal leaves in a rosette, to +40 cm long, oblong, elliptic, or lanceolate, variously lobed, spiny-margined, glabrous to arachnoid pubescent. Cauline leaves alternate, variously lobed, spiny-margined, sessile with bases decurrent on stem and forming wings, glabrous to arachnoid pubescent.

Inflorescence - Single flower head terminating stem. Head usually nodding, 5-8cm broad.

Involucre - Outer phyllaries spine-tipped, lanceolate, typically recurved, reflexed or spreading, greenish purple, with prominent midvein, to +1.3cm long, +1cm broad at base. Inner phyllaries with weak spine or none, erect to spreading, purple, with prominent midvein. Phyllaries mostly glabrous or with arachnoid pubescence at base.

Carduus nutans involucreInvolucre.

Ray flowers - Absent.

Disk flowers - Corolla dark pink, to +1.5cm long, 5-lobed. Stamens 5, mostly included. Style exserted well beyond corolla, pinkish to lilac at apex. Achenes glabrous, 4mm long, striped. Pappus of capillary bristles.

Carduus nutans flowers

Flowering - May - October.

Habitat - Pastures, prairies, waste ground, disturbed sites, roadsides, railroads.

Origin - Native to Europe.

Other info. - This is a very aggressive species which spreads rapidly because of the large number of achenes produced by each plant.
The fruit can travel great distances with the wind because of the large, silky pappus.
The nodding nature of the mature flower heads gives rise to the species name. "nutans" which means "nodding".
This plant can be seen along the sides of virtually every road in the state during the summer.
A plan to eradicate the plant is underway using a beetle, a Curculionid I think, who's larva eats the fruits of the plant before they mature. I have seen the larvae in action and they do inflict some serious damage.

Photographs taken at Flemming Park, Jackson County, MO., 5-13-00.


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