Fern | Description, Features, Evolution, & Taxonomy | Britannica
WEBSep 19, 2024 · 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, genetics, evolutionary history, and classification.
Fern - Spore, Rhizome, Frond | Britannica
WEBSep 19, 2024 · Root. Fern roots are generally thin and wiry, although some are fleshy and either slender (in the Ophioglossaceae) or as much as 13 mm (0.5 inch) in diameter (e.g., Acrostichum and Marattia). The relation of the roots to …
fern summary - Encyclopedia Britannica
WEBfern, 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).
Fern - Shape, Structure, Reproduction | Britannica
WEBSep 19, 2024 · The basic spore shape among ferns is tetrahedral; the proximal face (the one facing inward during the tetrad, or four-cell, stage following reduction division, or meiosis) is made up of three sloping planes, and the distal, or outer, face consists of a single rounded surface.
Fern - Medicinal, Ornamental, Food | Britannica
WEBSep 19, 2024 · The typical fern, a sporophyte, consists of stem, leaf, and root; it produces spores; and its cells each have two sets of chromosomes, one set from the egg and one from the sperm.
Tree fern | Growing, Propagation & Maintenance | Britannica
WEBInstead of the bark and wood that characterize the trunks of seed plant trees, the trunks of tree ferns are composed of rhizomes modified to grow vertically and embedded in a dense mantle of adventitious roots. These trunks may reach heights of 25 metres (80 feet) or more in some species.
lower vascular plant - Encyclopedia Britannica
WEBLower vascular plant, any of the spore-bearing vascular plants, including the ferns, club mosses, spike mosses, quillworts, horsetails, and whisk ferns. Modern studies have shown that, as a group, the plants are not evolutionarily …
Whisk fern | Ferns, Psilotum, Vascular Plants | Britannica
WEBwhisk fern, either of the two species of the primitive fern genus Psilotum in the family Psilotaceae of the order Psilotales and the class Psilotopsida of the division Pteridophyta (the lower vascular plants). A whisk fern has water- and food-conducting tissues but lacks true leaves and roots.
Osmunda | Royal Fern, Fern Family & Rhizomes | Britannica
WEBOsmunda, fern genus of the family Osmundaceae, with divided fronds and often growing to a height of 1.5 metres (5 feet). The matted fibrous roots of these abundant ferns are called osmunda fibre, osmundine, or orchid peat; they are broken up and used as a rooting medium for epiphytic orchids (those.
Fern - Evolution, Development, Reproduction | Britannica
WEBSep 19, 2024 · Stems erect and mostly trunklike (to 25 metres, [82 feet]) or less commonly creeping or sprawling to short-ascending, scaly near the tip (sometimes also hairy) and usually with a mantle of roots; leaves mostly large (up to 5 metres [about 16 feet]), but in a few species only 10–40 cm (about 4–16 inches), 1 to 4 times pinnately compound ...