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Jacob's Ladder
Polemonium caeruleum
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A perennial alpine plant endemic to Japan (Polemoniaceae is rare in Japan), growing in subalpine zones of Hokkaido and central Honshu. Numerous blue-purple small flowers bloom in clusters. The pinnate compound leaves resemble the fern Davallia (shinobu), giving rise to the Japanese name.
Identification Points
- โNumerous blue-purple 5-petaled flowers in clusters
- โOdd-pinnately compound leaves with many leaflets (ladder-like, hence 'Jacob's Ladder')
- โGrows in alpine and subalpine grasslands
Habitat
Alpine to subalpine grasslands of Hokkaido and central Honshu
Season
JulyโAugust (flowers)
Morphological TraitsAI-estimated, needs verification
Growth form
Herb
Leaf type
Compound
Flower color
Purple
Habitat
Mountain
Petal count
Many
Petal fusion
Fused
Stipules
Absent
Flower symmetry
Actinomorphic
Ovary position
Superior
Plant sex
Hermaphrodite
Stamen count
5
Phylogenetic Positionใใใทใใ็ง โ
Phylogenetic Position
Angiosperms > Eudicots > Core Eudicots > Ericales > Polemoniaceae
Divergence Era
Paleogene (ca. 40 million years ago)
Evolution Notes
Polemoniaceae is centered in North America, with only a few related species in Japan. The blue-purple sympetalous flowers are a classic example of alpine flowers pollinated mainly by bumblebees.
View on evolution timeline โSources & References
AI-generated, needs verification