Hymenophyllum cupressiforme
common filmy-fern
Southeastern Australia and New Zealand
Overview
Hymenophyllum cupressiforme is a small evergreen filmy fern with translucent fronds only one cell thick, growing from a slender creeping rhizome that mats over damp surfaces. The fronds are 0.8-4 inches (2-10 cm) long, deep green, finely divided, and pressed into a flattened, cypress-like outline that gives the species its name. Because the frond tissue lacks a protective cuticle, the plant absorbs and loses water directly through its surface and survives only where the air stays close to saturated. It grows in deep shade on moist rock faces, boulders, and the bases and trunks of trees in cool, wet forest and gully systems. Spores form in small cup-shaped structures along the frond margins and disperse on moist air. Hymenophyllum cupressiforme spreads slowly to form low, moss-like colonies and has very low tolerance of drying, direct sun, and wind. In cultivation it is confined to terrariums, fern houses, and permanently shaded, humid grottoes, and it cannot survive ordinary garden exposure.
Native Range
Hymenophyllum cupressiforme is native to southern and eastern Australia, including Tasmania, and also occurs in New Zealand. It grows in cool, wet forest, gullies, and gorges on shaded rocks and tree bases where humidity stays high year-round.Suggested Uses
H. cupressiforme is grown in terrariums, wardian cases, fern houses, and permanently shaded, humid rockwork. It forms a low, moss-like green cover over damp stone and bark. Its strict humidity needs rule out open garden use.How to Identify
Appearance
Size & Dimensions
Height1" - 4"
Width/Spread4" - 1'
Reaches mature size in approximately 3 years
Bloom Information
As a fern, H. cupressiforme produces no flowers. It reproduces by spores formed in small marginal cups, released mainly in the warmer, moist months. New fronds unfurl through spring and summer where humidity remains high.
Detailed Descriptions
Foliage Description
Deep greenGrowing Conditions
Sun Requirements
Tolerates up to 2 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow H. cupressiforme in deep shade with constant high humidity, such as a closed terrarium, fern house, or shaded grotto. It needs moisture-retentive, free-draining substrate of bark, peat, or rock kept permanently damp with soft or rainwater. The fern suits cool conditions, roughly 40-68F (4-20C), and is damaged by heat, drying air, and direct sun. Keep air movement gentle and humidity near saturation, as even brief drying kills the fronds. It tolerates light frost where humidity stays high but not freezing of the substrate.Pruning
H. cupressiforme needs no pruning. Remove browned or dead fronds gently to reduce mould in enclosed setups. The thin rhizome mat regrows slowly, so disturbance sets colonies back.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons