The fern pictured was found in Stairs Gulch, Big Cottonwood Canyon, Salt Lake City, Utah.
Ferns are vascular plants differing from the more primitive lycophytes by having true leaves (megaphylls). They differ from seed plants (gymnosperms and angiosperms) in their mode of reproductionólacking flowers and seeds. Like all other vascular plants, they have a life cycle referred to as alternation of generations, characterized by a diploid sporophytic and a haploid gametophytic phase. Unlike the gymnosperms and angiosperms, the ferns' gametophyte is a free-living organism.
Ferns don't reproduce with seeds, instead they fling little spores out which then grow into new ferns.
Polypodiales may be regarded as one of the most evolutionarily advanced orders of monilophytes (ferns), based on recent genetic analysis. They arose and diversified about 100 million years ago, probably subsequent to the diversification of the angiosperms.
The term "pteridophyte" has traditionally been used to describe all seedless vascular plants, making it synonymous with "ferns and fern allies".
Life cycle of a typical fern:
1. A sporophyte (diploid) phase produces haploid spores by meiosis. 2. A spore grows by mitosis into a gametophyte, which typically consists of a photosynthetic prothallus. 3. The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis. 4. A mobile, flagellate sperm fertilizes an egg that remains attached to the prothallus. 5. The fertilized egg is now a diploid zygote and grows by mitosis into a sporophyte (the typical "fern" plant).
Many ferns depend on associations with mycorrhizal fungi. Many ferns only grow within specific pH ranges; for instance, the climbing fern (Lygodium) of eastern North America will only grow in moist, intensely acid soils, while the bulblet bladder fern (Cystopteris bulbifera), with an overlapping range, is only found on limestone.
New leaves typically expand by the unrolling of a tight spiral called a crozier or fiddlehead. This uncurling of the leaf is termed circinate vernation. Leaves are divided into three types:
* Trophophyll: A leaf that does not produce spores, instead only producing sugars by photosynthesis. Analogous to the typical green leaves of seed plants. * Sporophyll: A leaf that produces spores. These leaves are analogous to the scales of pine cones or to stamens and pistil in gymnosperms and angiosperms, respectively. Unlike the seed plants, however, the sporophylls of ferns are typically not very specialized, looking similar to trophophylls and producing sugars by photosynthesis as the trophophylls do. * Brophophyll: A leaf that produces abnormally large amounts of spores. Their leaves are also larger than the other leaves but bear a resemblance to trophopylls.
Bracken fern is most commonly used today as a food for humans. The newly emerging croziers or fiddleheads are picked in spring and may be consumed fresh or preserved by salting, pickling, or sun drying. Both fronds and rhizomes have been used in brewing beer, and rhizome starch has been used as a substitute for arrowroot. Bread can be made out of dried and powered rhizomes alone or with other flour. American Indians cooked the rhizomes, then peeled and ate them or pounded the starchy fiber into flour. In Japan starch from the rhizomes is used to make confections. Bracken fern is grown commercially for use as a food and herbal remedy in Canada, the United States, Siberia, China, Japan, and Brazil and is often listed as an edible wild plant. Powdered rhizome has been considered particularly effective against parasitic worms. American Indians ate raw rhizomes as a remedy for bronchitis.