Welted thistle |
Flower
head, involucre, upper and lower leaf surface of
Carduus
crispus
| Carduus crispus ssp. crispus L.: | |
| Blooming period: | June–September |
| Height: | 30–150 cm |
| Flowers: | in heads, Ø of the heads 15–25 mm, stamens: 5, styles: 1 |
| Ray florets: | missing |
| Disc florets: | purple |
| Calyx: | transformed into a pappus |
| Stem leaves: | alternate, pinnatifid, spiny toothed |
| Basal leaves: | 10–20 cm long, narrowing into a stalk or petiole winged |
Plant biennial or perennial, herbaceous, with slender taproot.
Stem erect, branched, breakable, spiny winged.
Stem leaves alternate, decurrent, pinnatifid or pinnatipartite, undersides of the leaves grey tomentose or with woolly hairs, upper leaf surface without without spines or bristles, margins spiny toothed.
Lower leaves large, elliptical to oblong, pinnatifid, rarely undivided, sometimes short-stalked, leaves losing upwards in size, sessile. Leaves in the upper area broad-linear, sometimes undivided.
Flower heads rarely solitary, usually 3–5 ones clustered on common stalks, which are about 4 cm long at the flowering period, leafless, spiny winged and felty-white. Receptacle flat and bristly.
The phyllaries are arranged scale-like in 7 or 8 rows. The outer and the middle ones are lanceolate to spiniform, upright to spreading and bearing a 1–1.5 mm long spine. The inner phyllaries are upright and membranous and pointed at the end. Phyllaries arachnoid. Involucre almost spherical.
The flower head consists entirely of purple or rarely white, filiform, 11–26 mm long tubular florets, that are hermaphrodite and 5-dentate. At the base without chaffy leaves.
After pollination by bees, bumblebees or butterflies, the inferior ovary forms an approximately 4 mm long nut fruit (achene), which is yellow-brown to gray-brown and slightly flattened. It bears about 12 mm long sailing hairs, that are not feathery but possibly weakly branched and white.
Carduus crispus can form hybrids with C. acanthoides, C. defloratus, C. nutans and C. personata.
Besides Carduus crispus ssp. crispus with tomentose lower leaf surfaces, in Germany still exist the subspecies Carduus crispus ssp. occidentalis with greenish and sparsely hairy ones.
| Floral formula: |
| * K=pappus [C(5) A5(connate)] G(2) inferior |
Occurrence:
On
path and roadsides, wastelands, ruderal areas. Prefers slightly warm,
moist,
slightly alkaline and very nitrogen-rich locations.
Distribution:
Originally
Eurasia and Africa, introduced in North America.