Vascular plants, those with specialized tissue for the circulation of water and nutrients, evolved more than 400 million years ago. Early vascular plants have no wood, no flowers nor seeds. They reproduce from spores which are pollinated and dispersed by the wind. Their root and shoot systems enable them to thrive in many habitats. Living decedents of the most ancient ones are found everywhere except Antarctica.
The first ferns appeared in the mid-Devonian Period 383 million years ago. The earliest types are now extinct. The first modern fern families evolved 250 million years ago. Today ferns are the second most diverse group of vascular plants. There are over 10,000 living species of ferns!
A fern garden in the Leiden Botanical Gardens in Holland.
The plants that come to mind when we think “fern” have distinctive leaves called fronds and rhizomatous roots. The spores are found on the underside of the leaflets. Some species form clumps while others form colonies. All ferns want a shady to semi-shady setting. Their tolerance for wet spots varies widely.
There are many ferns native to our deciduous forests. They range in size from tiny ground huggers to statuesque six-footers. Some are evergreen. Others are dormant in winter. The spring unfurling of fiddlehead ferns is a uniquely wonderful sight. Most natives are quite cold tolerant and not fussy about pH. They generally like soil enriched with organic matter.
Club mosses are another branch of the fern family. The scale-like leaves press tightly along the stem looking something like a little green club. Sphagnum moss and narrow leaf peat moss are among the numerous members of the clan. Club moss tea has been used as a remedy for many ailments since ancient times in both the Old World and the New. It acts as a diuretic and so is thought to be helpful in treating kidney and urinary tract problems as well as diarrhea.
Believe it or not, horsetail reeds are also related to ferns. They appeared about 350 million years ago and are native to North America, Europe and Asia. These distinctive-looking plants have leafless stems reinforced with silica. Most of them flourish in a wet environment. They reproduce from spores which explode from little bulbs on top of the stems and by rhizomes. The rhizomes can grow as deep as six feet.
Sometimes Home Depot carries plants for water gardens. I picked out a small cup of horsetails to add to my bog garden.
They have flourished, crowding out other plants. Because they are native they cannot be called “invasive” but rather are “aggressive” in colonizing an environment. I winnow the horsetails about three times a year. The spores form in early spring. Remove and bag these for disposal before they ripen. Mine have not been able to spread beyond the bog, but if I could turn back time, I would plant them in a sunken container.
(Photos--Above right: Fiddlehead ferns. Above left: fern spores. At right is a photo of my bog garden. Horsetails are in the foreground, right.)
Along with their allies the lycophytes, ferns dominated the Carboniferous Period (369-299 million years ago). During this time Earth developed a greenhouse gas problem due to volcanic activity. When plants died, they sank into anoxic swamps. Without oxygen there were no micro-organisms to decompose them. Their burial created most
of the coal and natural gas deposits known today.
Master gardener Ann Bartlett in her current series is working her way forward from the botanical dawn of time. Last week she did mosses. Next week: cycads! Access Ann's earlier articles from the gardening icon on the homepage or by clicking Columns, then Gardening in the Navigator above.