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Giant Fern
Angiopteris lygodiifolia
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A large fern growing on moist forest floors in Okinawa and Ogasawara. The fleshy stipules (auriculate stipules) at the base of the petiole are conspicuous. A single frond can reach 2β3 m in length, making it a giant fern known as a primitive eusporangiate fern.
Identification Points
- βA pair of large, fleshy stipules at the petiole base (characteristic of Marattiaceae)
- βFronds are large, bipinnate, 1β3 m long
- βSporangia are fused into synangia
Habitat
Moist forest floors and ravines in Okinawa and Ogasawara
Season
Year-round (evergreen)
Morphological TraitsAI-estimated, needs verification
Evergreen/Deciduous
Evergreen
Leaf type
Compound
Phylogenetic Positionγͺγ₯γ¦γγ³γΏγ€η§ β
Phylogenetic Position
Vascular plants > Polypodiophyta > Marattiopsida > Marattiales > Marattiaceae
Divergence Era
Carboniferous (approx. 320 million years ago onward)
Evolution Notes
Marattiaceae originated approximately 350 million years ago in the Carboniferous period. Among extant ferns, it retains many primitive features, particularly in the structure of its synangia (fused sporangia).
View on evolution timeline βSources & References
AI-generated, needs verification