Hymenophyllum spp.
filmy ferns
Wet tropical and temperate forests worldwide
Overview
Hymenophyllum spp. is a genus of roughly 250 filmy ferns in the family Hymenophyllaceae, found in humid forests through the tropics and into cool temperate rainforests worldwide, including parts of the Pacific Northwest, southern South America, New Zealand, and western Europe. The fronds are membranous and translucent, in most species only a single cell layer thick, lacking the waterproof cuticle of typical leaves. This structure leaves the plants wholly dependent on constant moisture in the surrounding air, and they grow only where humidity stays high, on dripping rock faces, stream banks, and the trunks and branches of trees in shaded, sheltered places. Plants are small, with creeping wiry rhizomes and fronds 0.5-8 inches (1-20 cm) long that form dense, moss-like mats. The frond divisions are narrow, with margins entire or toothed, and reproduction is by spores held in tiny two-lipped cups along the frond edges rather than by flowers. The genus dries out and dies quickly if the air becomes dry, which limits cultivation to terrariums, wardian cases, and humid shade houses. Growth is slow, and colonies build up over many years.
Native Range
Found in humid forests across the tropics and in cool temperate rainforests of New Zealand, southern South America, western Europe, eastern Asia, and parts of North America, growing on wet rock and tree bark in deep shade.Suggested Uses
Grown in terrariums, wardian cases, and bottle gardens, and on shaded, constantly damp walls or rockwork in cool greenhouses. In suitably humid climates the ferns colonize shaded stonework, tree-fern trunks, and grotto plantings. The genus is collected by fern specialists and bryophyte enthusiasts for closed, humid displays.How to Identify
Appearance
Size & Dimensions
Height1" - 8"
Width/Spread2" - 1'
Bloom Information
Ferns do not flower. Reproduction is by spores produced in small marginal cups, released mainly in the warmer, moist months. New fronds unfurl whenever humidity and temperature allow.
Detailed Descriptions
Foliage Description
translucent 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
Grows in deep to partial shade on constantly moist, acidic substrates with a pH near 4.5-6.5, rooting in bark, peat, moss, or rock crevices rather than open soil. Air humidity must stay high at all times, which usually means a terrarium, wardian case, or shaded, sheltered site near water. Water is applied as a soft misting or by keeping the substrate and surrounding air damp with lime-free water. Strong light, dry air, and temperature extremes quickly scorch the filmy fronds. Growth is slow and the plants are intolerant of drying out even briefly. Cool to mild temperatures suit most species, with tropical kinds needing more warmth.Pruning
Dead or damaged fronds are picked off to keep colonies healthy. No cutting back is needed, as the plants are small and slow-growing. Spreading mats can be divided carefully to start new colonies.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons