Carduus nutans L.
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.
Upper stem.
Lower 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.
Involucre.
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.
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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