Hybrid welted thistle |
Flower heads, pappus and leaf of the hybrid welted thistle
| Carduus × polyacanthus Schleich.: | |
| Blooming period: | June–September |
| Height: | 30–150 cm |
| Flowers: | in heads, Ø of the heads 20–30 mm, stamens: 5, styles: 1 |
| Ray florets: | missing |
| Disc florets: | purple |
| Calyx: | transformed into a pappus |
| Stem leaves: | alternate, pinnatifid, spiny toothed |
| Basal leaves: | 10–30 cm long, petiole winged |
Plant biennial or perennial, herbaceous, with 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 spines or bristles, margins spiny toothed.
Lower leaves large, elliptical to oblong, pinnatifid, rarely undivided, sometimes short-stalked, losing upwards in size, sessile. Leaves in the upper area broad-linear, sometimes undivided.
Flower heads solitary or 2–4 ones clustered on leafless stalks, which are not spiny winged in the upper part, but felty-white. Flower heads usually slightly nodding. Receptacle flat and bristly.The phyllaries are arranges in several rows. The outer and the middle ones are lanceolate, reflexed to spreading, with spike tip. The interior ones are also lanceolate, erect or protruding and pointed. Phyllaries sometimes cobwebby. Involucre spherical to hemispherical.
The flower heads consist entirely of purple or rarely white, filiform, about 13 mm long tubular florets, which are hermaphrodite and 5-dentate, at the base without chaffy leaves.
After pollination by bees, bumblebees or butterflies, the inferior ovary forms an up to 4 mm long nut fruit (achene), but often the achenes are developed incomplete and are sterile. It bears about 13-20 mm long sailing hairs, that are not feathery but possibly weakly branched and white. Plants very diversiform!
Carduus × polyacanthus is a hybrid of C. crispus and C. nutans.
| Floral formula: |
| * K=pappus [C(5) A5(connate)] G(2) inferior |
Occurrence:
On
path and roadsides, wastelands, ruderal areas. slightly warm, slightly
alkaline and nitrogen-rich locations.
Distribution:
Arises
where both parental
species occur. Originally Eurasia and North Africa, in North America
the parents have been introduced.