Difference Between Horsetails and Ferns

Vascular Cryptogams

• Ferns and horsetails are both vascular cryptogams, a loose group of plants allied by their physical structure and methods of reproduction. The “vascular” reflects the special tubing within the inner tissue that transfers waters and nutrients throughout the plant. “Cryptogam,” as translated by Daniel Mathews in his 1988 “Cascade-Olympic Natural History,” means “hidden mating,” and suggests the inconspicuous routes of regeneration – the release of tiny spores. Many taxonomists now place the horsetails – the Equisetopsida – with the various classes of ferns in a large group of vascular cryptogams, the Pteridophyta.

Horsetails

• Extant horsetails belong to the genus Equisetum, and are among the most striking-looking of all plants. They arrived on the evolutionary scene at least 325 million years ago, and their unmistakable appearance seems perfectly reflective of that far distant Upper Carboniferous Period. They were among the dominant plants in those archaic forests, whose modern legacy are some of the world’s great coal beds. Horsetails grow from underground rhizomes that send up tough, silica-rich stalks. Certain species have stiff whorls of branches staggered along the stalk, giving the genus its common name. Some members of Equisetum that lack the bristling branches and manifest above ground as asparagus-like stems are called scouring-rushes. That moniker suggests the abrasive nature of horsetail stalks, which derives from their silicate component.

Ferns

• The specific taxonomy of ferns is still the subject of much debate and scrutiny. Thousands of species exist around the world, displaying a grand variety of appearances. Many grow from sunken rhizomes, as in horsetails, with each frond, however intricate, constituting a single leaf. That foliage comes in a range of compositions, such as pinnately compound – as in the enormously widespread bracken fern.

Ecology

• Horsetails commonly grow in damp or waterlogged environments, as from the spongy, sometimes-inundated ground flanking a forest stream. Some species can be truly enormous, like the giant horsetail of Latin America: This biggest of its kind may rear over 20 feet tall in swamps, ditches and other moist environments (see Resources section). Ferns collectively exhibit huge ecological variety, growing from deserts to steaming rainforests. Some species, like the licorice fern of the Pacific Northwest, commonly grow on the trunks and branches of trees.