''Polemonium'', commonly called Jacob's ladders or Jacob's-ladders (the name derived from the Biblical story), is a genus of between 25 and 40 species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family Polemoniaceae, native to cool

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

regions of the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

. One species, '' Polemonium micranthum'', also occurs in the southern

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. Many of the species grow at high altitudes, in mountainous areas. Most of the uncertainty in the number of species relates to those in Eurasia, many of which have been synonymized with '' Polemonium caeruleum''. ''Polemonium'' are

perennial plant In horticulture, the term perennial (''wikt:per-#Prefix, per-'' + ''wikt:-ennial#Suffix, -ennial'', "through the year") is used to differentiate a plant from shorter-lived annual plant, annuals and biennial plant, biennials. It has thus been d ...

s (rarely

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. Globally, 6% of all plant species and 15% of herbaceous plants (excluding trees and shrubs) are ...

s) growing 10–120 cm tall with bright green

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

divided into lance-shaped leaflets. They produce blue (rarely white or pink)

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s in the spring and summer. Some species are used as food plants by the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of some

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

species including '' Coleophora polemoniella''.

Species

Kew Kew () is a district in the London Borough of Richmond upon Thames. Its population at the 2011 census was 11,436. Kew is the location of the Royal Botanic Gardens ("Kew Gardens"), now a World Heritage Site, which includes Kew Palace. Kew is ...

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

accepts 37 species. Many are locally known simply as "Jacob's ladder". *'' Polemonium acutiflorum'' – tall Jacob's ladder *'' Polemonium boreale'' – northern Jacob's ladder *'' Polemonium brandegeei'' – Brandegee's Jacob's ladder *'' Polemonium caeruleum'' – Jacob's ladder (the original plant to bear this name); charity *'' Polemonium californicum'' – showy Jacob's ladder *'' Polemonium campanulatum'' *'' Polemonium carneum'' – royal Jacob's ladder *'' Polemonium caucasicum'' *'' Polemonium chartaceum'' – Mason's Jacob's ladder *'' Polemonium chinense'' *'' Polemonium confertum'' – Rocky Mountain Jacob's ladder *'' Polemonium eddyense'' – Mount Eddy Jacob's-ladder *'' Polemonium elegans'' – elegant Jacob's ladder *'' Polemonium elusum'' – elusive Jacob's-ladder *'' Polemonium eximium'' – sky pilot *'' Polemonium foliosissimum'' – towering Jacob's ladder *'' Polemonium glabrum'' *'' Polemonium grandiflorum'' *'' Polemonium hingganicum'' *'' Polemonium kiushianum'' *'' Polemonium majus'' *'' Polemonium mexicanum'' *'' Polemonium micranthum'' – annual polemonium *'' Polemonium nevadense'' – Nevada Jacob's ladder *'' Polemonium occidentale'' – western Jacob's ladder *'' Polemonium pauciflorum'' – few-flower Jacob's ladder *'' Polemonium pectinatum'' – Washington Jacob's ladder *'' Polemonium pulchellum'' *'' Polemonium pulcherrimum'' – beautiful Jacob's ladder *''

Polemonium reptans ''Polemonium reptans'' is a perennial plant, perennial herbaceous plant native to eastern North America. Common names include spreading Jacob's ladder, creeping Jacob's ladder, false Jacob's ladder, abscess root, American Greek valerian, blue bel ...

'' – Jacob's ladder, Greek valerian *'' Polemonium sachalinense'' *'' Polemonium schizanthum'' *'' Polemonium schmidtii'' * ''Polemonium'' × ''speciosum'' *'' Polemonium sumushanense'' *'' Polemonium vanbruntiae'' – Vanbrunt's Jacob's ladder * ''Polemonium'' × ''victoris'' *'' Polemonium vilosissimum'' *'' Polemonium villosum'' *'' Polemonium viscosum'' – sticky polemonium *'' Polemonium yezoense''

References

Polemoniaceae genera {{Polemoniaceae-stub