Fern | Description, Features, Evolution, & Taxonomy | Britannica
Fern, class of several thousand species of nonflowering vascular plants that reproduce by spores. Ferns have true roots, stems, and complex leaves and constitute an ancient division of plants. Learn about their physical characteristics, life cycle, …
Fern - Spore Dispersal, Photosynthesis, Moisture | Britannica
Fern - Spore Dispersal, Photosynthesis, Moisture: Ecologically, ferns are most commonly plants of shaded damp forests in both temperate and tropical zones. They may show structural adaptations to rocky habitats or to living as epiphytes.
List of ferns | Types, Species, Varieties | Britannica
Ferns (division Pteridophyta) are an ancient group of nonflowering vascular plants. They have true roots, stems, and complex leaves and reproduce by spores. Ferns can be found nearly worldwide and more than 9,000 extant species are known to science. The …
fern - Students | Britannica Kids | Homework Help
The familiar fern plant is the sporophyte. To summarize: ferns produce spores; spores produce prothallia; in the prothallia grow eggs and sperm; sperm fertilize eggs; fertilized eggs grow into large fern plants. Ferns are generally classed in their own division, Pteridophyta.
Fern - Medicinal, Ornamental, Food | Britannica
Fern - Medicinal, Ornamental, Food: Many species are a source of food and medicine. The greatest economic value is in horticulture and biological research. The typical fern, a sporophyte, consists of stem, leaf, and root, usually perennial, and reproduces vegetatively.
Fern - Shape, Structure, Reproduction | Britannica
Fern - Shape, Structure, Reproduction: The basic spore shape is tetrahedral. Most ferns are homosporous, while a few have dimorphic spores. Gametophytes form when the spore wall cracks under appropriate moist conditions.
Fern - Spore, Rhizome, Frond | Britannica
Fern - Spore, Rhizome, Frond: Steles exhibit diverse patterns: most common ferns possess a dictyostele, separated by regions known as leaf gaps; there are also numerous siphonostelic ferns and some protostelic ferns.
Fern - Evolution, Development, Reproduction | Britannica
2024年9月19日 · Fern - Evolution, Development, Reproduction: The actual origins of the vegetative organs of ferns are still unknown. It is suggested that the original fern stem was protostelic; the leaf is equally or even more problematic as to its ultimate origin.
Fern - Sporangia, Gametophytes, Alternation | Britannica
Fern - Sporangia, Gametophytes, Alternation: The sex organs of ferns are the antheridium and the archegonium. Within the archegonial venter the zygote undergoes cell divisions to form the embryo, which usually has a development distinctive to ferns.
fern summary | Britannica
fern, Any of about 10,000–15,000 species (class Polypodiopsida) of nonflowering vascular plants that have true roots, stems, and complex leaves and reproduce by spores. Ferns come in a wide variety of sizes and shapes. Many are small fragile plants, while others are treelike (see tree fern).