What Kind of Ferns Have Stems?

Tree Ferns

• Tree ferns not only have aboveground stems, but they have very tough, woody stems that can grow up to 80 feet tall. All 800 species of tree ferns are endangered and most grow in humid semitropical to tropical regions. The hapu'u or Hawaiian tree fern (Cibotium glaucum) grows to 20 feet tall with a 15-foot spread. It has bright green, deeply dissected fronds and a dark brown, fibrous stem. The New Zealand tree fern (Dicksonia squarrosa) reaches heights of 25 feet. It has a brown, fibrous stem and low-growing green fronds. Both of these tree ferns are grown as ornamental landscape trees.

Aboveground Stems

• A few other ferns have aboveground stems, including the bracken fern (Pteridium aquilinum), a perennial that grows in wet to dry forests, meadows and boggy or sandy areas. Though this fern has rhizomes, they grow aboveground and create branching stems. The bracken fern grows to 4 1/2 feet tall and has branched, spatula-shaped fronds covered with slightly hairy leaflets. The stem emerges from the ground as a hairy, dark-brown base and turns yellow and hairless at the top.

  The southern lady fern (Athyrium asplenioides) also has a partially aboveground stem. This deciduous fern grows from 1 to 3 feet tall and spreads slowly. It prefers partial to full shade and moist, fertile soil. Southern lady ferns have deep red stems, from which emerge feathery, twice-pinnate fronds.

Stolon Ferns

• A few ferns also have underground stems known as stolons. Stolons differ from rhizomes in that they grow from a rhizome, forming a new underground stem. Some stolons grow aboveground as well, such as those of the Kupukupu fern (Nephrolepis cordifolia). This Hawaiian native thrives on lava fields and in wet to dry forests across the tropics. It grows to 2 feet tall and has narrow, lustrous fronds that range from yellow-green to dark green. Kupukupu has stolons that develop underground tubers. The tuberous sword fern (Nephrolepis cordifolia) also has tuberous stolons. This species grows up to 3 feet tall and has light yellow stolons. It spreads aggressively and is considered an invasive species in some regions.

Rhizome Ferns

• Most ferns have rhizomes or underground stems. Ornamental species include the lowland brittle fern (Cystopteris protrusa), which grows from 6 to 18 inches tall. It has a small rhizome but spreads quickly. Lowland brittle ferns have deciduous fronds with bi- or tri-pinnate pinnules. The log fern (Dryopteris celsa) grows to 40 inches tall. It has a black rhizome and dark-green, semi-evergreen fronds with pinnate leaflets. The log fern's natural habitat includes fallen logs and swampy areas.