Pretty Jacob’s Ladder – Polemonium pulcherrimum

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Alaska Wildflowers | Purple

The purple flowers of pretty Jacob's ladder (Polemonium pulcherrimum) in the Alaska interior.

Pretty Jacob’s Ladder

Polemonium pulcherrimum

Common Names

beautiful Jacob’s ladder
pretty Jacob’s ladder
showy Jacob’s ladder
skunkleaf polemonium

Synonyms

none


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Subspecies

P. pulcherrimum ssp. delicatum
P. pulcherrimum ssp. lindleyi
P. pulcherrimum ssp. pulcherrimum

Genus: Polemonium (Jacob’s ladder)
Family: Polemoniaceae (phlox)
Order: Ericales
full classification


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Duration – Growth Habit

Perennial – Forb/herb

Identification and Information

Pretty Jacob’s ladder (frequently called showy Jacob’s ladder or beautiful Jacob’s ladder) is a blue or purple-flowering perennial herb that grows from a taproot and branched rhizome. There are three currently accepted subspecies, two of which are found in Alaska (P. pulcherrimum ssp. lindleyi and P. pulcherrimum ssp. pulcherrimum are found in Alaska, P. pulcherrimum ssp. delicatum is only found in the American Southwest). The plant can grow up to 50 cm (20 inches) tall, although the pulcherrimum variety that is found in Alaska is typically shorter than 20 cm (8 inches). The main differences between varieties are size and leaflet size.

The plant is hairy with several stems. The leaves are green, alternate, pinnately divided, and mostly basal. Leaves on the stems are fewer and smaller than the basal leaves. Leaves are composed of up to14 pairs of ovate to ovate-lanceolate leaflets, 2-5 mm long (sometimes larger but under 1 cm) and 5mm wide.

The terminal inflorescence is a cyme of a few to several flowers with one flower on the main stem and others attached via pedicels that are typically longer than the corolla tube. The flowers are asexual containing both stamens and ovary. Each flower has a calyx (sepals) that is 5-lobed and united, 4-6 mm long. When in fruit, the capsule is contained within the calyx. The corolla is composed of 5 united blue or purple petals with a yellow bell or “eye” in the center. The corolla tube is about 7-12 mm long. Each flower has 5 stamens (with white filaments and anthers) attached to the base of the corolla tube. The ovary is superior and the pistil is just slightly longer than the stamens.



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Uses

For information only (typically historical) – I take no responsibility for adverse effects from the use of any plant.

The Thompson (Nlaka’pamux, Ntlakyapamuk) Native American tribe of British Columbia has used the plant as a dermatological aid.

Distribution and Habitat

Pretty Jacob’s ladder is widely distributed across western North America and eastern Siberia. A few isolated specimens are reported in the GBIF database but are not found elsewhere. This includes Mexico, Illinois, Iowa, West Virginia, and Connecticut.

P. pulcherrimum can be found in tundra, alpine and subalpine terrain, roadsides, and grassy areas, typically in sandy or gravelly soils. It lives in both shady and sunny areas.

Classification

RankScientific Name (Common Name)
KingdomPlantae (plantes, Planta, Vegetal, plants)
   SubkingdomViridiplantae (green plants)
      InfrakingdomStreptophyta (land plants)
         SuperdivisionEmbryophyta 
            DivisionTracheophyta (vascular plants, tracheophytes)
               SubdivisionSpermatophytina (spermatophytes, seed plants, phanérogames)
                  ClassMagnoliopsida 
                     SuperorderAsteranae 
                        OrderEricales 
                           FamilyPolemoniaceae (phlox)
                              GenusPolemonium L. (Jacob’s-ladder)
                                 SpeciesPolemonium pulcherrimum (skunkleaf polemonium, pretty Jacob’s-ladder)
 Direct Children:
                                    SubspeciesP. pulcherrimum ssp. delicatum (beautiful Jacob’s-ladder, skunkweed Jacob’s-ladder)
                                    SubspeciesP. pulcherrimum ssp. lindleyi (Jacob’s-ladder)
                                    SubspeciesP. pulcherrimum ssp. pulcherrimum (pretty Jacob’s-ladder)

References and Further Reading

Guidebook

Field Guide to Alaskan Wildflowers, Pratt, Verna E. pg. 4

Classification and Taxonomy

P. pulcherrimum Hook. Taxonomic Serial No.: 31023, ITIS Database

P. pulcherrimum Hook. Jacob’s-ladder, USDA Database

Uses

P. pulcherrimum ssp. lindleyi (Wherry) V. Grant, Native American Ethnobotany Database

Map and Distribution

P. pulcherrimum Hook. Published in: Bot. Mag. 57: t. 2979 (1830), GBIF Database

P. pulcherrimum Showy Jacob’s-ladder, NatureServe Explorer

Description and Information

P. pulcherrimum showy polemonium, Burke Herbarium Image Collection: University of Washington

Showy Polemonium, Showy Jacob’s-ladder, Jacob’s-ladder, Skunk-leaved Polemonium, Paul Slichter – science.halleyhosting.com

P. pulcherrimum : Showy Jacob’s-ladder, Central Yukon Species Inventory Project

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