Carolina Thistle (Cirsium carolinianum (Walt.) Fern. & Schub.)


Family – Asteraceae

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

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.

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).

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.

Photographic Location – Falls Creek Falls State Park TN.

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. It would make a good garden subject as it requires no care and has practically no spines compared to other members of the genus.

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