Stop and smell the … ferns
One of my favorite times to observe ferns is in winter when they stand out in the brown leaf-litter. Of the 70 or so species that have been documented in the southern mountains, perhaps a fourth are evergreen. These would include walking fern, rockcap fern, resurrection fern, intermediate wood fern, several of the so-called “grape fern” species, and others.
The evergreen fern I can always count on finding is Christmas fern, which occurs in rocky woodlands. It is the most common evergreen fern in WNC, just as the New York fern is our most common deciduous fern.
Christmas fern appears in bouquet-like clusters from a scaly rhizome. The fiddleheads (emerging fronds) that appear in spring are covered with silvery scales. The mature fronds can be up to 28 inches in length.
The fertile spore-producing fronds of Christmas ferns are narrow at their tips. Look on the underside of a fertile tip and you’ll see the clusters of cases in which the dust-like spores develop.
Many Christmas fern fronds are simply vegetative and don’t display the narrowed tips or spore cases. The fertile fronds are always taller than the vegetative fronds, so as to allow for wind dispersal of the spores.
Home gardeners should be aware that once the spores are shed, the fertile tips turn brown and wither. It’s part of the plant’s natural life cycle, not an indication that your Christmas ferns are dying. Also remember that the old fronds will wither, turn brown, and fall off as the plant makes room for new ones.
The patterns in which spore cases are arranged is often the essential clue used to differentiate various otherwise similar fern species. But identifying Christmas fern doesn’t require that sort of scrutiny. It is readily identified by the distinctive shape of the leaflets (pinna) that make up the leafy (blade) portion of the frond above its stem (stipe)
Each leaflet resembles Santa’s sleigh when viewed on a horizontal plane or a Christmas stocking when held vertically. This holiday motif is sounded again in the common name “Christmas fern,” which arose because the species was used by the earliest New England settlers for Christmas decorations. They are still frequently cut or used as potted plants for seasonal arrangements.
The roots were used by the Cherokee as an ingredient in emetics, as an external application for rheumatism, and in a decoction for toothache, chills, and bowel complaints.
When examining Christmas ferns in the wild, keep in mind that leaflet and blade shapes will often vary from plant to plant or even on the same plant. The leaflets especially vary in the amount of serration.
Jesse M. Shaver’s Ferns of the Eastern Central States with Special Reference to Tennessee (1954) is an older manual that I still use a lot because it’s one of the few guides that depicts the variant forms for each fern species. His descriptions and illustrations of the Christmas fern variants take up 13 pages, describing six distinctive forms.
Murray Evans, the retired plant taxonomist and fern authority at the University of Tennessee, noted in his Ferns of the Smokies (2005) that, “There are many named varieties and forms for this species based on peculiar and conspicuous leaf variations, but none are considered important taxonomically.”
But they are interesting to locate and observe.