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Flowering Rush
Butomus umbellatus
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A perennial aquatic plant native to Eurasia. Rarely confirmed as naturalized in Japan. It bears erect, triangular, slender leaves and produces an umbellate inflorescence atop a long flowering stalk in summer, with beautiful pale pink flowers having 6 tepals.
Identification Points
- βLeaves are triangular in cross-section, erect from the base, 0.5β1 m long
- βFlowers have 6 pale pink tepals, borne in umbellate inflorescences
- βSpreads via rhizomes in waterside mud
Habitat
Waterside, wetlands, and irrigation channels (native to Eurasia; rarely naturalized in Japan)
Season
JuneβSeptember (flowers)
Morphological TraitsAI-estimated, needs verification
Growth form
Herb
Leaf shape
Linear
Habitat
Aquatic
Leaf arrangement
Alternate
Leaf type
Simple
Venation
Parallel
Leaf margin
Entire
Petal count
6 petals
Petal fusion
Free
Leaf dissection
Undivided
Flower symmetry
Actinomorphic
Ovary position
Superior
Plant sex
Hermaphrodite
Latex
Present
Phylogenetic Positionγγγ€η§ β
Phylogenetic Position
Angiosperms > Monocots > Alismatales > Butomaceae
Divergence Era
Late Cretaceous to Paleogene (ca. 85 million years ago)
Evolution Notes
Butomaceae belongs to Alismatales and is a relatively basal aquatic monocot. It retains the primitive feature of numerous free carpels.
View on evolution timeline βSources & References
AI-generated, needs verification