Fauna
Plant

ʻAmaʻu Fern

Sadleria cyatheoides

Also known as Amaumau Fern, Amauma'u Fern, Ama'u

ʻAmaʻu ferns colonize fresh volcanic basalt across the Hawaiian Islands, acting as vital pioneer plants that build organic soil on young lava flows. Emerging fronds flush a brilliant bright red or bronze to protect tender young tissues from intense sun and solar radiation. Over time, mature plants develop a woody trunk resembling a miniature tree fern, forming a critical understory layer in native wet forests.

EndemicLava PioneerTree Fern
ʻAmaʻu Fern reference1 / 7
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & preyAutotrophic
Predators
  • Feral Pigs
  • Feral Goats
  • Invasive Slugs
ThreatsFeral ungulate browsing, invasive weed encroachment, habitat loss
HabitatsVolcanic lava fields, wet montane forests, subalpine shrublands
Life span20–50 years
Classification
  1. FamilyBlechnaceae
  2. SpeciesSadleria cyatheoides
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Safe to observe at a normal distance.
What to notice
Recognized by its small trunk and bright red emerging fronds growing on Hawaiian lava fields or forest understories.
Support conservation
Clean hiking boots before entering native forest reserves to avoid spreading invasive plant seeds and fungal pathogens.
Responsible observation
  • Spotting Red Flush: Look for bright orange and crimson young fronds unfurling near the center of the crown.
  • Trail Etiquette: Stay on designated lava boardwalks and paths to protect fragile emerging roots and crusts.
Related species
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