Cyclosorus hudsonianus

leaf Main Plant Information





Hawaiian Names with Diacritics

  • Laukahi

Hawaiian Names

  • Laukahi

Common Names

  • Hudson's air fern
  • Hudson's maiden fern


  • Pneumatopteris hudsoniana

leaf Plant Characteristics

Distribution Status


Endangered Species Status

No Status

Plant Form / Growth Habit

  • Non-Woody, Spreading

Mature Size, Height (in feet)

  • Fern/Fern-like, Tall, Greater than 3

Mature Size, Width

Laukahi is known to have a 4-foot spread.

Life Span

Long lived (Greater than 5 years)

Landscape Uses

  • Accent
  • Container
  • Ground Cover

Plant Produces Flowers


leaf Leaf Characteristics

Plant texture

  • Coarse

Additional Plant Texture Information

The fronds grow to about 60 inches long.

Leaf Colors

  • Medium Green

leaf Pests and Diseases

Additional Pest & Disease Information

This fern is prone to ants, spider mites, mealy bugs and scale.

leaf Growth Requirements


A 13-13-13 slow release fertilizer with minor elements is beneficial every six months for plants in pots. For larger potted ferns showing poor color or not producing crosiers (fiddleheads or emerging fronds), use a complete fertilizer at half the recommended strength. Do not till solid fertilizers into soil because ferns have a shallow root system. [1]

Pruning Information

Trim spent fronds for a clean landscape appearance.

Water Requirements

  • Moist

Additional Water Information

Laukahi prefers moist conditions but can tolerate wet conditions.

Light Conditions

  • Partial sun
  • Shade

Additional Lighting Information

Laukahi prefers partial shade but can tolerate full shade.

leaf Environmental Information

Natural Range

  • Kauaʻi
  • Oʻahu
  • Molokaʻi
  • Lānaʻi
  • Maui
  • Hawaiʻi

Natural Zones (Elevation in feet, Rainfall in inches)

  • Less than 150, 50 to 100 (Mesic)
  • Less than 150, Greater than 100 (Wet)
  • 150 to 1000, 50 to 100 (Mesic)
  • 150 to 1000, Greater than 100 (Wet)
  • 1000 to 1999, 50 to 100 (Mesic)
  • 1000 to 1999, Greater than 100 (Wet)
  • 2000 to 2999, 50 to 100 (Mesic)
  • 2000 to 2999, Greater than 100 (Wet)

Additional Habitat Information

This endemic fern is common locally in mesic to wet forests on all major islands from 65 to about 2,500 feet.

leaf Special Features and Information

General Information

Laukahi is a member of the Marsh Fern family or Thelypteridaceae.


The generic name Cyclosorus refers to the round sori (Greek kyklos, circle + soros, heap) or spores located under the fronds. [2]

The specific epithet hudsonianus is named for Navy Capt. William Leverreth Hudson (1794-1862), commander of the Peacock, one of the U.S. Exploring Expeditions (1838-1842).

Early Hawaiian Use

 No known use.

Additional References

[1] Kay Lynch, Lāʻau Hawaiʻi

[2] Taxonomic changes in Hawaiian ferns and lycophytes. Records of the Hawaii Biological Survey for 2009–2010, page 15.

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