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Tall Jacob’s-ladder
Growing form
Perennial herb.
Height
25–50 cm (10–20 in.). Stem unbranched, lower part glabrous, upper part long-haired, also with glandular hairs.
Flower
Corolla broadly campanulate (bell-shaped), blue–purple (occasionally white), 15–20 mm (0.6–0.8 in.) broad, fused, deeply 5-lobed. Lobes elliptic, with tapered tips, with fringed margins, throat hairy. Calyx 5-lobed. Stamens 5. Gynoecium composed of 3 fused carpels. Inflorescence a sparsely flowered raceme.
Leaves
Alternate, lowest leaves stalked, upper leaves short-stalked, stalk edged, grooved, edges hairy or sometimes almost glabrous. Blade pinnate, lowest leaves usually 8-paired at most, pinnate. Leaflets lanceolate–narrowly ovate, with tapered and sharp tips, with entire margins, glabrous. Leaflets separate from each other.
Fruit
Roundish, yellowish, capsule with 3 compartments.
Habitat
Meadows, hedgerows, stream banks, river banks, roadsides, ruins, old logging sites.
Flowering time
July–August.

Tall Jacob’s ladder spread to northern Finland sometime after the last Ice Age, but there are different theories about where it originally came from. According to one theory it survived somewhere along Norway’s ice-free coast and spread from there to its current habitat. According to another theory, however, the plant has spread from the south, following the retreating ice. Tall Jacob’s ladder’s natural habitat has probably been Lapland’s bare lower alpine tundra, flood-influenced meadows and rich swamps. Even at the beginning of the 20th century hay was made from natural meadows to feed domestic animals and tall Jacob’s ladder and other meadow plants’ seeds spread to people’s yards. The majority of the plant’s current habitat nowadays includes meadows that are slowly returning to their wild state, shops and inhabited areas, logging sites and roadsides. Tall Jacob’s ladder brings to mind a bygone era of which all that might be left is the rotting log frame of a wilderness cabin. Tall Jacob’s ladder should be able to find sufficient new territory beside highways, but at least until now it hasn’t really succeeded in spreading to the habitats created by contemporary people.

Tall Jacob’s ladder’s Finnish name comes from its flowers’ resemblance to harebell, but the former’s corolla is much more deeply lobed than the Bellflower family, and thus looks as if the leaves are separate. Tall Jacob’s ladder’s close relative Jacob’s ladder (P. caeruleum) is very similar, and they were formerly classed as subspecies of the same species, and the species issue has still not been satisfactorily concluded in many people’s minds. Jacob’s ladder is rarer in the wild and likes broad-leaved forests in the south of Finland, but it is commonly cultivated as an ornamental in Lapland too, and it transplants easily to and from gardens. Jacob’s ladder produces a lot of flowers, and their smaller, flatter petals are usually without ciliate edges. The upper part of Jacob’s ladder’s stem is short-haired, while the upper part of tall Jacob’s ladder’s stem has long glandular hairs. Additionally, Jacob’s ladder’s leaves have more leaflets and their edges often touch.

Polemonium acutiflorum

Taxonomie

Classe

Ordre

Famille

Genre