(tall Jacob's-ladder)
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Photo of Polemonium acutiflorum by Jacob Frank
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Tall Jacob's ladder is an herb with pinnately divided leaves and purple, five-petalled flowers found in moist to wet meadows and shrub thickets across Denali. Plants have a solitary stem, hairless towards the base, with
glandular hairs above, 15-40 cm tall. The leaves of this plant are
glabrous (or mostly
glabrous), the margins dark. Leaves are pinnately divided, the segments
lanceolate or
elliptic. Plants bear several
perfect light purple flowers from leaf
axils or the very top of the stem. The
corolla is fused, broadly bell-shaped with a white throat lined with purple veins. The bell flares into five lobes, broadly triangular, the margins lined with hairs. The shape of the petals distinguishes from other
Polemonium species in the study area, and gives it its name—'acutiflorum', meaning acute-tipped flowers. Flowers contain
stigmas with three curled lobes and five
stamens with bright yellow
anthers. Fruits are a dry
capsule containing a few small seeds.
Tall Jacob's ladder is perennial and
deciduous. It flowers mid-summer.
Polemonium species are
monoecious with bisexual flowers. There have been no studies on the reproduction of Tall Jacob's ladder. The genus
Polemonium is insect pollinated (primarily by bees). Fruits release numerous small seeds, dispersed by wind and gravity.
Tall Jacob's ladder is an incompletely circumpolar species; its range extends east from Alaska to the edge of Northwest Territory and south to Alberta, and westwards through the Russian and Fennoscandian arctic. The species is widespread and common in Alaska, from the Aleutians to the northern coast, albeit rare or absent in Southeast. Polemonium acutiflorum is common in Denali, particularly in the Alaska Range area on both sides of the crest.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
In Denali, this is primarily an alpine and subalpine species. This species occurs at a wide range of elevations (122-1548 m), with a peak at 900-1100 meters. Though it occurs commonly on all inclines, it is slightly more common on gentle slopes with an average of 9.47 degree inclines and it has a 25% frequency of occurrence on slopes of 4-12 degrees. There is a very slight preference for northern aspects.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Wet to moist sites.
