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Gunnera family
Gunneraceae
グンネラ科
A monotypic family of about 40 species in the genus Gunnera, distributed in temperate to tropical highland regions of the Southern Hemisphere. Ranges from giant herbs with leaves exceeding 2 m in diameter to small forms. Notable as the only angiosperm harboring endosymbiotic cyanobacteria (Nostoc) in stems for nitrogen fixation.
Key Characteristics
- ●Some species have gigantic leaves (over 2 m in diameter)
- ●Cyanobacteria symbiotic in stems and petioles for nitrogen fixation
- ●Flowers very small, numerous in spike-like inflorescences
- ●Mostly rhizomatous perennials
- ●Fruits are small drupes
Morphological Traits
A family may include species with different trait values — multiple values indicate the range within the family.
Leaf arrangement
Alternate
Leaf type
Simple
Venation
Palmate
Leaf margin
Serrate / Dentate / Entire
Growth form
Herb
Evergreen/Deciduous
Deciduous
Leaf dissection
Dissected / Undivided
Stipules
Present / Absent
Petal count
3 petals / 4 petals / 5 petals
Ovary position
Inferior
Stamen count
1-2
Plant sex
Dioecious / Monoecious
Phylogenetic Position
Angiosperms > Eudicots > Core eudicots > Gunnerales > Gunneraceae
Divergence Era
Late Cretaceous to Paleogene (approx. 80 million years ago)
Representative Genera
Related Evolution Events
- ・Nitrogen fixation through cyanobacterial symbiosis (unique among angiosperms)
- ・Bidirectional diversification toward both leaf gigantism and dwarfism
Plants in Gunnera family on this site
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