Image: Wikimedia Commons (See link for license)
Chain Fern
Blechnum niponicum
シシガシラ
A fern growing on mountain forest floors and along ravines. Characterized by pronounced dimorphism between sterile and fertile fronds. The sori on fertile fronds are arranged in continuous lines along the midrib.
Identification Points
- ✓Sterile and fertile fronds clearly dimorphic
- ✓Sori in long continuous lines parallel to the pinna midrib
- ✓Fronds pinnate, firm, and coriaceous
Habitat
Mountain forest floors and along ravines
Season
Year-round (spores summer–autumn)
Morphological TraitsAI-estimated, needs verification
Growth form
Herb
Leaf type
Compound
Habitat
Mountain
Phylogenetic Positionシシガシラ科 →
Phylogenetic Position
Vascular plants > Polypodiophyta > Polypodiopsida > Polypodiales > Blechnaceae
Divergence Era
Cretaceous (ca. 100 million years ago–)
Evolution Notes
Blechnaceae shows pronounced dimorphism between sterile and fertile fronds, representing a fern group that has specialized for efficient spore dispersal.
View on evolution timeline →Sources & References
AI-generated, needs verification