Phylum Monilophyta: Class Psilotopsida (Ferns)With their large fronds, ferns are the most readily recognizable seedless vascular plants.
Tracheophytes can be divided into two groups of seedless plants: the lycophytes (club mosses, spike mosses, and quillworts) and the ferns (including horsetails and whisk ferns); and two groups of seed-bearing plants: the gymnosperms (cycads, pines, spruces, firs, etc.)
The primitive nature of the whisk fern is underscored by its having flagellated sperm, unlike the more advanced flowering plants, the angiosperms. The simple branched stems of Psilotum recalls the structure of the rhyniophytes, and the whisk fern is unique among living vascular plants in its lack of roots and leaves.
Bryophytes don't have vascular tissue. Bryophytes all reproduce using spores rather than seeds and don't produce wood, fruit or flowers. Their life-cycle is dominated by a gametophyte generation which provides support and nutrients for the spore producing growth form known as the sporophyte.
Vascular plants evolved true roots made of vascular tissues. Because of lignin, stems are stiff, so plants can grow high above the ground where they can get more light and air. Because of their vascular tissues, stems keep even tall plants supplied with water so they don't dry out in the air.
Horsetails are related to ferns in that they have a vascular system. They never developed the ability to reproduce with seeds.
Ferns are mostly homosporous, though some are heterosporous. The heterosporous state is a more advanced condition, that seems to have evolved independently in several groups of plants. The haploid spores are formed by meiosis inside the sporangium.
Seedless vascular plants include ferns, horsetails and clubmosses. These types of plants have the same special tissue to move water and food through their stems and foliage, like other vascular plants, but they don't produce flowers or seeds. Instead of seeds, seedless vascular plants reproduce with spores.
Ferns are seedless, vascular plants. They contain two types of vascular tissue that are needed to move substances throughout the plant. Evolutionarily, this addition of vascular tissue to plants is what allowed ferns to grow up and out rather than just spreading along the ground.
The vascular bundle includes two main kinds of tissue: xylem and phloem.
Seed vascular plants share the characteristic of having a vascular system of internal tubes that transport life-sustaining liquids from the roots to all areas of stem and leaves, similar to a circulatory system in animals.
Plants that have xylem - water-carrying tubes - and phloem - food-carrying tubes - are called vascular and are what you generally think of when you think of plants. Gymnosperms are plants that have seeds but no flowers. Examples of these are pine trees or conifers.
Ferns are primitive plants that have no flowers or seeds and reproduce by spores. They do have vascular tissue, however -- the xylem that conducts water and the minerals dissolved in it from the roots, and the phloem that transports food from the leaves.
Note that sperm and egg may be produced on the same gametophyte, so a fern may self-fertilize. Advantages of self-fertilization are that fewer spores are wasted, no external gamete carrier is required, and organisms adapted to their environment can maintain their traits.
Fern xylem offers many distinctive features: (1) presence of numerous vessels and various numbers of tracheids in most species; (2) presence of vessels in both roots and rhizomes in virtually all species; (3) presence of specialized end walls in vessels of only a few species; (4) multiple end-wall perforation plates in
Ferns and Other Seedless Vascular Plants. Ferns, club mosses, horsetails, and whisk ferns are seedless vascular plants that reproduce with spores and are found in moist environments.
Hornworts are minute nonvascular plants, similar in size to liverworts. They also have very fine rhizoids and lack stems.
The life cycle of the fern has two different stages; sporophyte, which releases spores, and gametophyte, which releases gametes. Gametophyte plants are haploid, sporophyte plants diploid. This type of life cycle is called alternation of generations. To follow the life cycle of the fern, begin at number one below.
Key PointsClub mosses, which are the earliest form of seedless vascular plants, are lycophytes that contain a stem and microphylls. Horsetails are often found in marshes and are characterized by jointed hollow stems with whorled leaves. Photosynthesis occurs in the stems of whisk ferns, which lack roots and leaves.
It is found in tropical Africa, Central America, tropical and subtropical North America, South America, tropical Asia, Australia, Hawaii, southern Japan and even a few spots in SW Europe. Whisk ferns apparently are quite common in Central Florida. They often pop up in nursery stocks and are viewed by some as a weed.
Liverworts, hornworts, and mosses are the examples of bryophytes. These are non-vascular plants i.e. do not contain xylem and phloem tissues. Spikemosses, clubmosses, ferns, quillworts are the examples of pteridophytes. They are termed as vascular plants as they contain xylem and phloem tissues.
Ferns are plants that do not have flowers. Ferns generally reproduce by producing spores. Similar to flowering plants, ferns have roots, stems and leaves.
Their closest relatives, technically are the class Psilotopsida, which consists of whisk-ferns and grape-ferns. The reason these ferns are the closest relatives is because they all are part of the larger classification known as Eusporangiate ferns.
The Psilotales are the least complex of all terrestrial vascular plants, and were once believed to be remnants of an otherwise extinct Devonian flora. This is primarily because psilophytes are the only living vascular plants to lack both roots and leaves.
The gametophyte generation (that which produce gametes—male and female) is very reduced and short. A more ancestral trait of ferns is for the gametophyte to actually be subterranean (hidden underground).
Reproduction by SporesFerns and horsetails have two free-living generations: a diploid sporophyte generation (spore-producing plant) and. a haploid gametophyte generation (gamete-producing plant).
The seedless vascular plants include club mosses, which are the most primitive; whisk ferns, which lost leaves and roots by reductive evolution; and horsetails and ferns. Ferns are the most advanced group of seedless vascular plants.
Whisk fern is a small plant, growing six to 12 inches tall, and with many branches. The stems have green and yellow nodes that are actually the reproductive structures. Green are immature, yellow mature. It does not produce flowers or go to seed.
Seedless nonvascular plants are small. The dominant stage of the life cycle is the gametophyte. Without a vascular system and roots, they absorb water and nutrients through all of their exposed surfaces.
Occurrence. Moreover, microphylls occur in lycophytes and horsetails while megaphylls occur in angiosperms, gymnosperms, and the fronds of ferns.
Whisk ferns produce a branching rhizome that is covered in hair-like projections called rhizoids. These structures not only help anchor the plant in place, they also function in a similar way to roots.
