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A pteridophyte is a vascular plant (with xylem and phloem) that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden. They are also the ancestors of the plants we see today.
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers.They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase.
In various classification schemes, these may be grouped as classes or divisions within the plant kingdom. Fern allies and ferns were sometimes grouped together as division Pteridophyta. [1] Another traditional classification scheme of living plants is as follows (here, the first three classes are the "fern allies"): Kingdom: Plantae
Polystichum setiferum, a fern Grimmia pulvinata, a moss Pelvetia canaliculata, a brown alga Hypholoma fasciculare, a fungus. A cryptogam (scientific name Cryptogamae) is a plant, in the broad sense of the word, or a plant-like organism that share similar characteristics, such as being multicellular, photosynthetic, and primarily immobile, that reproduces via spores rather than through flowers ...
For comparison, humans have 46 chromosomes, consisting of n = 23 pairs. Ophioglossum malviae from the Western Ghats in India has been characterized as the world's smallest terrestrial pteridophyte with plants typically 1–1.2 cm in size. [5]
The following phylogram shows a likely relationship between the other vascular plant classes and the leptosporangiate ferns. It was formerly unclear about the relationship between Equisetopsida , Psilotopsida , and Marattiopsida , [ 14 ] [ 15 ] [ 16 ] but recent studies have shown that Equisetopsida is most likely sister to Psilotopsida.
Azolla (mosquito fern, water fern, fairy moss) is a genus of seven species of aquatic ferns in the family Salviniaceae.They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling the form of some mosses or even duckweeds.
The plants have intercalary meristems in each segment of the stem and rhizome that grow as the plant gets taller. This contrasts with most seed plants, which grow from an apical meristem - i.e. new growth comes only from growing tips (and widening of stems). Horsetails bear cones (technically strobili, sing. strobilus) at the tips of some stems.