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Comments are encouraged and appreciated. We are amateur botanist, and we do make mistakes sometimes with our identifications. We strive to make this a good identifying resource. All comments are moderated by me and may take several days to appear. This is due to the high number of inappropriate comments that have nothing to do with this subject.

Saturday, June 9, 2012

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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