From a botanical standpoint, the primary difference begins with taxonomy and geographical origin. The Boston fern is not a distinct species but rather a specific cultivar of a wild species. Its scientific name is Nephrolepis exaltata 'Bostoniensis'. It originated as a mutant of the Nephrolepis exaltata (Sword Fern) species discovered in a Boston nursery shipment in 1894. In contrast, "other fern varieties" encompass a vast array of genera and species from across the globe, such as Platycerium (Staghorn Ferns), Adiantum (Maidenhair Ferns), Davallia (Rabbit's Foot Ferns), and Asplenium nidus (Bird's Nest Fern). Each of these belongs to different families within the Pteridophyte division, meaning their relation to the Boston fern can be quite distant evolutionarily.
The morphology of the fronds (leaves) is a key identifying feature. The Boston fern is celebrated for its gracefully arching fronds. Each frond is pinnately compound, meaning a central rachis (stem) has numerous small leaflets (pinnae) arranged oppositely along its length. The cultivar is characterized by its "soft" texture and the way the pinnae are slightly wavy or twisted, creating a fuller, more draping appearance compared to the stiffer, more upright fronds of its Sword Fern parent. Other ferns exhibit radically different frond structures. For instance, the Staghorn Fern (Platycerium) has two distinct frond types: sterile, flat shield fronds that anchor the plant and fertile, antler-like fronds. The Bird's Nest Fern (Asplenium nidus) produces simple, undivided, strap-like fronds that emerge from a central rosette, resembling a bird's nest.
All ferns reproduce via spores rather than seeds, but the location and structure of the spore-producing organs (sori) are critical for identification. On Boston ferns, the sori are located on the undersides of the pinnae (leaflets). They are typically kidney-shaped (reniform) and arranged in rows on either side of the midvein. This is a common trait among many nephrolepis species. However, other fern varieties have vastly different sori placement and morphology. Maidenhair ferns (Adiantum) have their sori tucked under reflexed, flap-like portions of the pinnae margin. Staghorn ferns produce their spores on large, brown, felt-like patches on the underside of the fertile fronds. The Bird's Nest Fern has linear sori that run in parallel lines diagonally across the underside of the frond, a stark contrast to the discrete dots of the Boston fern.
While cultural needs can overlap, their innate physiological preferences differ. The Boston fern, hailing from tropical and subtropical regions of the Americas, thrives in high humidity, consistent moisture, and bright, indirect light. It is notoriously non-drought tolerant. Its hardiness is limited to USDA zones 9-11, making it exclusively a houseplant or seasonal annual in cooler climates. Other fern varieties have adapted to a wider range of ecological niches. The Christmas Fern (Polystichum acrostichoides) is a native North American species that is deciduous and remarkably cold-hardy (down to zone 3). The Rabbit's Foot Fern (Davallia) prefers its rhizomes to be slightly drier and is often grown in well-draining baskets. The Japanese Painted Fern (Athyrium niponicum) is grown as much for its cold tolerance as for its stunning silvery and burgundy foliage, preferring cooler conditions than a Boston fern could tolerate.
