Coast redwood (Sequoia sempervirens) trunks and sword ferns.
NPS
The bright green fronds you see peeking out of the forest floor at Muir Woods are most likely ferns. The plants referred to as “ferns and fern allies” are plants that have vascular tissue (xylem and phloem for conducting water and sugars), but do not produce fruits and seeds. Muir Woods is host to 13 species of ferns from six different fern families. Other seedless vascular plants include horsetails and club mosses.
Ferns and fern allies are different. Fern allies have microphylls (small leaves with a singular vein). Ferns have megaphylls (large leaves with several veins). Another difference is that fern allies have a specific branch used for reproduction called sporangia which looks like a pod. Ferns use the spores found on the back of their frond (leaf) for reproduction.
The reason that ferns do not produce seeds like most of the plants we know is that they are actually much older. Their reproductive strategy of producing spores instead of fruits has served them just fine since before the time of the dinosaurs! They reproduce during the gametophyte stage (sexual maturity stage of a plant). The sperm swim through the water to reach the egg. After the egg is fertilized, the plant will be at the sporophyte stage (asexual stage of a plant). The sporophyte will then become the ferns that we see today.
Ferns, similar to Coast Redwoods, can clone themselves. The difference is ferns can use underground horizontal stems called rhizomes to reproduce. The rhizome will break off and grow roots to create a clone. When succession (ecosystem change) happens, ferns can help the environment by taking over an area and provide habitat for many species. Ferns have been around for more than 300 million years, and have a worldwide distribution on all continents except Antarctica and most islands.
Here at Muir Woods watch for lady, sword, maiden hair, and gold back ferns to name a few. These ancient plants have something to tell us about permanence and adaptations that perhaps even the old growth redwood trees cannot.
Ladybugs overwintering on giant horsetail.
Stephanie Weinstein/ NPS
Giant horsetail is a fern ally, and the equisetum family has fossils that can be found over 300 million years ago. This ancient fern ally look like a segmented stem with many green sticks at each segment, and can be found close to water banks.
Coast Redwoods and western sword ferns.
NPS
Western sword ferns can grow from 2-6 feet tall, and is an evergreen (green leaves all year round) fern with fronds (leaves) that arch downward. An interesting fact is that they will have shorter fronds during times of drought to conserve water.
Lady Fern Fiddle head in forest.
Stephanie Weinstein/ NPS
Lady Ferns are 3 feet tall, and are deciduous (tree or shrub that will drop their leaves in the winter). Lady Ferns also have a 1 foot wide frond. Ferns have fiddleheads (tightly curled part) which will unfurl creating a new frond. Lady ferns can survive dry soils and a lot of sun, but tend to do better in wet and shaded environments.
For Further Reading:
Ditomasso, J.M., G.b. Kyser et al. 2013. Weed Control in Natural Areas in the Western United States. Weed Research and Information Center, University of California 544 pp.
“Fern Fossils.” University of Waterloo, https://uwaterloo.ca/earth-sciences-museum/resources/fern-fossils. Accessed 15 August 2021.
