Blechnaceae: Exploring the Diverse World of Chain Ferns
The Blechnaceae family, commonly known as the Chain Fern family, is a fascinating group of ferns that adds texture, structure, and resilience to gardens around the world. Belonging to the order Polypodiales, this family includes a mix of terrestrial, lithophytic, epiphytic, and even aquatic species. Gardeners prize these ferns for their distinctive frond forms, often reddish young growth, and their ability to thrive in shaded, damp environments.
Description and Distinctive Features of Blechnaceae
Blechnaceae ferns are perennial, herbaceous plants that range from small groundcovers to large, tree‑like species with trunk‑forming stems. Most species produce upright or arching fronds that form lush clumps. One striking characteristic is that young fronds often emerge in shades of red or bronze, maturing to deep green, which provides a striking seasonal contrast in shaded gardens.
Their fronds vary greatly in form, from simple, pinnately lobed leaves to complex, finely divided blades. In many genera, such as Blechnum and Woodwardia, the fertile fronds (those that produce spores) look very different from the sterile fronds, a feature known as dimorphism.
Frond stalks (petioles) typically contain multiple vascular bundles arranged in an arc, and the midribs are grooved on the upper side.
Reproductive Structures
Blechnaceae ferns reproduce via spores, like all true ferns. The sori (clusters of spore‑producing sporangia) are a key identifying feature of this family: they are elongate (rather than round, like in many other ferns) and often positioned along the veins or midribs of the leaflets. The sori are covered by a protective indusium, which opens toward the midvein as the spores mature.
Spores are typically bean‑shaped and lack chlorophyll, and the resulting gametophytes are green and heart‑shaped (cordate).
Habitat and Natural Range
Blechnaceae ferns thrive in humid, shady environments—from tropical rainforests to acid wetlands, including bogs and swamps. Some species grow on rocky crevices, while others climb trees as epiphytes, benefiting from filtered light and high humidity.
This family is most diverse in the Southern Hemisphere, especially in South America, Australasia, and the Pacific Islands, though several species also occur in temperate regions of the Northern Hemisphere.
Genera in the Blechnaceae Family
Botanists recognize 7–9 genera within Blechnaceae, comprising over 200 species. Some of the most important include:
- Blechnum – The largest genus, with species like Blechnum spicant (deer fern) and Blechnum occidentale.
- Doodia – Small ferns native to Australasia, often used ornamentally for their bright red emerging fronds.
- Woodwardia – Known for large, dramatic fronds, including Woodwardia fimbriata (giant chain fern), a favorite in woodland gardens.
- Parablechnum – Recently separated from Blechnum, containing species with unique growth habits.
Some members, particularly in Woodwardia and Blechnum, are cultivated for their ornamental appeal, especially in shade gardens.
Garden and Landscape Uses
Gardeners value Blechnaceae ferns for their architectural fronds, evergreen or semi‑evergreen foliage, and adaptability to shaded, moist locations. They are excellent choices for:
- Woodland gardens and shaded borders
- Bog gardens or areas near water features
- Rock gardens with consistently moist crevices
- Container planting for patios and shaded areas
Some larger species, like giant chain fern (Woodwardia fimbriata), provide dramatic focal points, while smaller species such as Doodia offer colorful, fine‑textured groundcover.
Key Takeaways
- Family: Blechnaceae (chain ferns)
- Habit: Mostly terrestrial, some lithophytic, epiphytic, or aquatic
- Fronds: Often reddish when young; dimorphic in many species
- Sori: Elongate, positioned along veins or midribs, with protective indusia
- Distribution: Cosmopolitan but most diverse in Southern Hemisphere tropics
- Genera: 7–9, including Blechnum, Doodia, Woodwardia, Parablechnum
- Uses: Ornamental ferns for shady, moist gardens, bogs, and woodland landscapes
Final Thoughts
The Blechnaceae family represents a diverse and highly adaptable group of ferns, perfect for gardeners looking to add year‑round greenery and textural variety to shaded and damp garden spaces. Whether planting the striking deer fern (Blechnum spicant), the giant chain fern (Woodwardia fimbriata), or colorful Doodia species, these ferns provide long‑lasting beauty and ecological value.
List of Genera in the Blechnaceae family of plants:
Subfamily Woodwardioideae
- Anchistea
- Lorinseria
- Woodwardia
Subfamily Stenochlaenoideae
- Salpichlaena
- Stenochlaena
- Telmatoblechnum
Subfamily Blechnoideae
- Austroblechnum
- Blechnidium
- Blechnopsis
- Blechnum
- Brainea
- Cleistoblechnum
- Cranfillia
- Diploblechnum
- Doodia
- Icarus
- Lomaria
- Lomaridium
- Lomariocycas
- Neoblechnum
- Oceaniopteris
- Parablechnum
- Sadleria
- Struthiopteris
