Microsorum musifolium 'Crocodyllus'

Early history and origin

Microsorum musifolium is a rainforest fern native from southern Myanmar through Malesia to New Guinea. It grows over tree surfaces in filtered light and humid air, spreading by creeping stems that receive frequent moisture without being buried in dense ground soil.

‘Crocodyllus’ first appeared as a mutation among tissue-cultured M. musifolium plants grown by Anthony John Osborne in Kuranda, Queensland. Further propagation showed that its dense growth and strongly raised netted veins remained stable, establishing it as a named selection. ‘Crocodyllus’, with a double “l”, is the original spelling; ‘Crocodylus’ is a later trade variant, not a separate cultivar.

Moisture and airflow for healthy fronds

• Grooming and propagation: Remove only fully dead fronds and leave the natural spore patches (sori) and raised veins intact. Divide rooted rhizome sections; plants raised from spores may not develop the same selected texture.
• Settle the rhizome first: Keep Microsorum ‘Crocodyllus’ warm, humid and in filtered light after delivery. Avoid immediate repotting or burying the creeping stem.
• Light: Use medium to bright filtered light without hard midday sun. Deep shade slows the production of new fronds.
• Water: Maintain even moisture while allowing drainage and air through the root zone. Repeated total drying crisps the fronds, while compact waterlogged media damage the rhizome.
• Substrate: Choose a coarse epiphytic fern mixture containing bark or fibre. Keep the scaly rhizome on or close to the surface, and use a shallow or wider container that is only modestly larger when repotting so the medium does not stay wet for too long.
• Temperature and humidity: Provide stable warmth and high humidity with gentle air movement.
• Feeding: While fresh fronds are forming, use a low-strength complete fertiliser and flush the mix occasionally to prevent salt accumulation.

Crocodile fern problems and fixes

• Sori or scale insects: Natural spore patches follow an organised vein-related pattern and produce no honeydew. Scale insects attach irregularly, may lift away and can leave sticky residue.
• Crisp tips and margins: Both drought and dead waterlogged roots can interrupt water supply; salts, dry air and excessive light add similar damage. Check medium moisture and rhizome firmness before watering.
• Yellow collapse with soft rhizome: The root zone has remained without enough air. Let surplus water escape, keep the creeping stem exposed and remove soft sections from a mature established fern.
• Bleached broad patches: Hard direct sun is the likely cause. Move ‘Crocodyllus’ into filtered light and leave partly green fronds until they die naturally.
• Brown old fronds at the rear: Normal turnover begins behind an advancing healthy rhizome. Remove only fully dead fronds when the growing end remains firm and active.
• Cottony rhizomes or fine stippling: Mealybugs hide along the creeping stem, while spider mites mark fronds in dry air. Separate the fern and inspect the rhizome and frond undersides before choosing a control.
• Holes in unfurling fronds: Look for slime trails and inspect the plant after dark. Hand-pick slugs or snails and reduce sheltered access to the pot.

Keep Microsorum musifolium ‘Crocodyllus’ away from children and pets

• Keep this plant away from children, cats and dogs.
• Its effects after chewing or swallowing are unclear, and plant material can still cause an upset stomach.
• Contact a veterinarian or medical professional if symptoms develop or do not settle.

Why is it called Microsorum musifolium?

Microsorum combines Greek mikros, small, with soros, heap, referring to the fern’s small spore clusters. Musifolium means banana-leaved and compares the broad fronds with leaves of Musa bananas.

Johann Heinrich Friedrich Link established the genus Microsorum in 1833 in Hortus Berolinensis, volume 2, page 110.

Carl Ludwig Blume first described it as Polypodium musifolium in 1828 in Enumeratio Plantarum Javae, volume 2, page 134. Edwin Bingham Copeland later placed it in Microsorum as Microsorum musifolium in 1929 in University of California Publications in Botany, volume 16, page 112.