Polemonium caeruleum L.
Jacob's ladder
Perennial with erect stems to c. 50 cm high; vegetative parts almost glabrous. Leaflets 18-22 (fewer in sub-floral lvs), sessile, 6-25 × 1-8 mm, linear-lanceolate or lanceolate; base broad-cuneate or rounded; apex acute. Cymes terminal, finely glandular-hairy, with up to 15 fls; lowest fls subtended by pinnate bracts with 3-7 leaflets. Pedicels usually < calyx at anthesis. Calyx 4-6 mm long; segments ovate-oblong, obtuse to subacute. Corolla ± rotate, c. 15 mm diam., white; tube c. 4 mm long; lobes rounded. Stamens with basal tuft of hairs. Style > stamens. Capsule 5-7 mm long, broad-ovoid, included in calyx tube. Seed 2.5-3 mm long, acutely 3-angled.
S.: C. Otago (road between Skippers and Shotover).
Temperate N. Hemisphere 1988
Very common in a young larch plantation, occupying around 2 or 3 hectares, cultivation escape.
FL Nov-Jan.
Apparently only the white form of Jacob's ladder is present in the wild. Also, the limited amount of material available from this wild population suggests that the leaflets are narrower than is usual in the blue form. The blue form is the one usually seen in gardens, where it grows and seeds itself prolifically, particularly in cooler parts of the country. The white form has been known as var. album.
