Cirsium carolinianum (Walt.) Fern. & Schub.

Cirsium altissimum plant

Family - Asteraceae

Stems - Erect, to +1.2m tall, branching above, hollow, herbaceous, tomentose to hirsute below, arachnoid pubescent above, carinate, from weak roots.

Cirsium altissimum stem

Leaves - Alternate. Lowest leaves petiolate. Petioles to +15cm long. Blade to +20cm long, +3cm broad. Cauline leaves sessile, linear-oblong, weakly lobed, with spines on margins only, greatly reduced above, to 15cm long(below), +/-1.5cm broad.

Cirsium altissimum leavesCauline leaves.

Inflorescence - Loose paniculate or cymose arrangement of flower heads terminating stems. Peduncles arachnoid pubescent, long, naked. Each peduncle typically subtended by a small foliaceous bract. Bracts arachnoid pubescent and prickle-margined.

Involucre - To 2cm tall(long), +/-1.5 in diameter, viscous. Phyllaries imbricate, tightly appressed, with a conspicuous whitish gland on midrib, sparse arachnoid pubescent to very sparse pilose, each tipped by a long thin bristle (to +3.5mm long).

Cirsium altissimum involucreInvolucre of late season or deprived plant.

Cirsium altissimum involucreInvolucre of healthy plant.

Ray flowers - Absent.

Disk flowers - Corolla rose-pink to pinkish-purple for most of length, whitish near base, to +/-2cm long, 5-lobed, glabrous. Lobes 3.5mm long, linear. Stamens 5. Anthers pinkish-purple, connate around style, typically exserted. Style rose-pink, well exserted, glabrous, 2.6cm long. Achenes (in flower) glabrous, white, 2mm long, angled. Pappus of white plumose bristles to 1.6cm long.

Cirsium altissimum flowers

Flowering - May - July.

Habitat - Rocky open woods, bluffs, ravines, valleys, thickets.

Origin - Native to U.S.

Other info. - This is an easy plant to ID in the field. The sticky phyllaries with their large whitish glands and long bristle tips are a dead give-away for the species, as well as the long, naked peduncles.
This species is only found in the southeast corner of Missouri. It would make a good garden subject as it requires no care and has practically no spines compared to other members of the genus.

Photographs taken CR 160-152, Mark Twain National Forest, Oregon County, MO., 7-14-00, and in Ellington, MO., 5-26-03.


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