Sword Fern

Edibility: 

Not typically consumed by humans. While not generally considered toxic, it's not a common food source.

Toxicity: 

Not generally considered toxic to humans or animals upon ingestion. The main concern is its invasive nature.

Uses: 

Widely cultivated as an ornamental plant in gardens, hanging baskets, and as indoor houseplants due to its attractive, lush foliage. Its robust nature makes it popular for landscaping.

Ecology: 

As an alien invasive plant in South Africa, Nephrolepis cordifolia is highly aggressive. It spreads extensively through its creeping rhizomes and prolific production of underground tubers, which store water and nutrients, allowing the plant to survive adverse conditions and quickly colonise new areas. It also reproduces effectively by microscopic spores that are wind-dispersed over long distances. It forms dense monocultures (single-species stands) on the forest floor, in moist woodlands, riparian zones, and disturbed areas, outcompeting and displacing indigenous herbaceous plants and suppressing the regeneration of native tree seedlings. Its dense growth can also alter soil conditions and microclimates.

Distribution and habitat: 

Widely cultivated as an ornamental plant throughout South Africa. It has naturalised and is considered an invasive species in many provinces, particularly in regions with high rainfall and suitable moist, shady conditions. It is common in the Eastern Cape (frequently found in coastal forests, moist woodlands, and along rivers around Kenton-on-Sea), KwaZulu-Natal, Mpumalanga, Limpopo, and Western Cape. It invades indigenous forests, plantations, moist woodlands, riparian zones, and shaded wasteland.

Derivation of name: 

• The genus name Nephrolepis comes from the Greek words 'nephros' (meaning "kidney") and 'lepis' (meaning "scale"), referring to the kidney-shaped indusium (a protective membrane covering the spore cases). 

• The species epithet cordifolia is Latin for "heart-leaved," referring to the heart-shaped base of its pinnae (leaflets). 

• The common name "Sword Fern" directly refers to the upright, stiff, and narrow sword-like shape of its fronds.

Historical aspects: 

Nephrolepis cordifolia has been widely cultivated as an ornamental fern for centuries due to its attractive foliage and ease of growth. Its hardiness, ability to thrive in various conditions, and prolific reproductive strategies (spores and tubers) made it popular for landscaping and indoor use. However, these same traits led to its escape from cultivation and establishment as a significant invasive species in many parts of the world, including South Africa, where it outcompetes indigenous flora, particularly in moist, shaded forest and riparian environments.

Plant family: Nephrolepidaceae (or sometimes placed in Davalliaceae or Dryopteridaceae, depending on classification system, but Nephrolepidaceae is often used for this genus).

NEMBA status: Category 1b invasive species. This means it must be controlled or eradicated where possible, and it is illegal to plant, propagate, import, or otherwise possess this plant without a permit.

Interesting facts:

• This fern hides a secret underground! It grows small, round, potato-like tubers on its roots, which store water and food, making it super tough and able to survive dry spells.

• Even though it looks delicate, this fern is a real survivor; it spreads like crazy using both tiny, dust-like spores (which are its "seeds") and those clever little underground tubers!

• Its common name, "Sword Fern," comes from its upright, stiff, and narrow fronds that genuinely look like tiny green swords poking out of the ground!

• Unlike flowering plants, ferns don't produce flowers or seeds. Instead, they release millions of microscopic spores from little bumps on the underside of their leaves!