North America Native Plant

Straight Lineleaf Fern

Botanical name: Antrophyum lanceolatum

USDA symbol: ANLA8

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Synonyms: Polytaenium feei (Schaffn. ex Fée) Maxon (POFE3)   

Straight Lineleaf Fern: A Unique Caribbean Native for Tropical Gardens Meet the straight lineleaf fern (Antrophyum lanceolatum), a fascinating tropical fern that breaks all the rules about what ferns should look like. Instead of the delicate, lacy fronds we typically associate with ferns, this Caribbean beauty sports simple, strap-shaped leaves ...

Straight Lineleaf Fern: A Unique Caribbean Native for Tropical Gardens

Meet the straight lineleaf fern (Antrophyum lanceolatum), a fascinating tropical fern that breaks all the rules about what ferns should look like. Instead of the delicate, lacy fronds we typically associate with ferns, this Caribbean beauty sports simple, strap-shaped leaves that look more like they belong on an orchid or bromeliad. If you’re gardening in a tropical climate and looking for something truly distinctive, this native Puerto Rican fern might just be your new favorite plant.

What Makes This Fern Special

The straight lineleaf fern is a perennial fern native to Puerto Rico, where it grows naturally in the island’s lush tropical forests. Unlike most ferns with their intricate, divided fronds, Antrophyum lanceolatum produces simple, linear leaves that are completely undivided – hence the straight lineleaf name. This unique characteristic makes it instantly recognizable and adds an architectural element to any garden setting.

As a member of the forb family, this fern lacks woody tissue and maintains its herbaceous nature throughout its life. It’s also known by the botanical synonym Polytaenium feei, which you might encounter in older botanical references.

Where You’ll Find It Growing

This tropical native calls Puerto Rico home, where it thrives in the island’s warm, humid climate. The fern is naturally adapted to the specific conditions found in Puerto Rican forests, making it perfectly suited for similar tropical and subtropical environments.

Growing Straight Lineleaf Fern Successfully

If you’re lucky enough to garden in USDA hardiness zones 10-12, you can successfully cultivate this unique fern. Here’s what you need to know:

Ideal Growing Conditions

  • Shade to partial shade – direct sunlight will scorch the leaves
  • High humidity levels (typical of tropical environments)
  • Well-draining, organic-rich soil
  • Consistent moisture without waterlogging
  • Good air circulation to prevent fungal issues

Planting and Care Tips

The straight lineleaf fern can be grown both as an epiphyte (growing on other plants) and terrestrially (in the ground). If planting in soil, ensure excellent drainage by incorporating plenty of organic matter like leaf mold or compost. The plant prefers a slightly acidic to neutral pH.

Water regularly to maintain consistent soil moisture, but never let the roots sit in standing water. In dry climates or indoor conditions, increase humidity around the plant by using a humidifier or placing it on a pebble tray filled with water.

Garden Design and Landscape Use

This fern’s unusual form makes it an excellent choice for adding textural contrast to tropical shade gardens. Its simple, linear fronds provide a striking counterpoint to the complex foliage of other tropical plants. Consider using it in naturalistic plantings that mimic Puerto Rico’s native forest understory, or as an epiphytic accent mounted on tree trunks or in hanging arrangements.

The straight lineleaf fern works particularly well in contemporary tropical garden designs where its clean, architectural lines complement modern landscaping aesthetics. It’s also perfect for collectors of unusual ferns or anyone looking to create an authentic Caribbean garden atmosphere.

Wildlife and Ecological Benefits

As a native Puerto Rican species, this fern plays a role in supporting local ecosystem health when grown in its native range. While it doesn’t produce flowers to attract pollinators (ferns reproduce via spores), it contributes to the overall biodiversity and provides habitat structure for small creatures in tropical forest ecosystems.

Is This Fern Right for Your Garden?

The straight lineleaf fern is an excellent choice if you garden in tropical zones and want something truly unique. Its unusual appearance makes it a conversation starter, and its native status in Puerto Rico means it’s well-adapted to tropical conditions. However, it’s definitely not suitable for temperate climates or areas that experience freezing temperatures.

If you’re outside the tropical zone but love the idea of simple-fronded ferns, consider researching native alternatives in your area that might provide similar architectural interest while being better suited to your local climate.

For tropical gardeners, the straight lineleaf fern offers the perfect combination of uniqueness, native plant benefits, and relatively straightforward care – as long as you can provide the humid, shaded conditions it craves. It’s a wonderful way to add a piece of authentic Caribbean forest to your own backyard paradise.

Straight Lineleaf Fern

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Vittariaceae Ching - Shoestring Fern family

Genus

Antrophyum Kaulf. - lineleaf fern

Species

Antrophyum lanceolatum (L.) Kaulf. - straight lineleaf fern

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA