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Alligator Weed
Alternanthera philoxeroides
ナガエツルノゲイトウ
A perennial herb native to South America, naturalized as an invasive species worldwide—sometimes called 'one of the world's worst invasive plants'. Designated as a 'Specified Invasive Alien Species' in Japan since 2005. It forms dense mats in wetlands and waterways.
Identification Points
- ✓Hollow stems that float on water
- ✓Opposite, oblong, glossy leaves
- ✓Small white ball-like inflorescences in leaf axils
Habitat
Rivers, ponds, paddy fields, wetlands (invasive)
Season
June to September (flowers)
Morphological TraitsAI-estimated, needs verification
Leaf arrangement
Opposite
Leaf type
Simple
Leaf shape
Oblong
Growth form
Herb
Flower color
White
Habitat
Wetland
Phylogenetic Positionヒユ科 →
Phylogenetic Position
Angiosperms > Eudicots > Core Eudicots > Caryophyllales > Amaranthaceae
Divergence Era
Late Cretaceous to Paleogene (ca. 80–65 million years ago)
Sources & References
📖Wikipedia 日本語版↗
🤖Claude AI生成（未確認）Wikipediaリードを根拠に生成。要確認。
AI-generated, needs verification