Introduction to pteridophytes - class-XI

Heterospory and heterophily are advanced traits found in genera like Selaginella, Salvinia, and Azolla. Psilotum, Lycopodium, Pteris, and Adiantum are generally homosporous and do not exhibit these traits.

The antheridium (male organ) is located on the lower surface of the fern prothallus and the archegonium (female organ) is located on the upper surface of the fern prothallus.

Cryptogams are defined as lower plants or plant-like organisms, that reproduce by spores. Vascular Cryptogams refers to those vascular plants, that do not make seeds.

In homosporous pteridophytes, the gametophyte (prothallus) is typically small, independent, and autotrophic, while the sporophyte is the dominant, independent, and autotrophic phase. Option A correctly identifies the autotrophic nature of the gametophyte.

Horsetail is in a family of plants containing about 35 species within the genus Equisetum. Scouring rush (Equisetum hyemale) is evergreen, with leafless, hollow, segmented stems with ash-colored bands. Stems grow to about 1/2 inch in diameter and reach up to five feet tall. Because the stems are rough and durable (due to their high silica content), they were called as scouring rushes, because early pioneers used them to scrub pots and pans. 

Vascular cryptogam is an old botanical phrase and it refers to those vascular plants that do not make seeds. Thus, cryptogam refers to the production of a separate, usually very small, archegoniate gametophyte. These are well represented in the fossil record.

Cryptogams are plants, that reproduce by spores without flowers or seeds but angiosperms possess flowers and seeds. Angiosperms are more advanced than the gymnosperms. They consist of covered seeds as compared to the naked seeds of the gymnosperms. Angiosperms bear true fruits. They show characteristics of double fertilization.

The spermatophyta comprises of all those land plants that produce flowers and seed. In angiosperms, and other seed plants, gametophytes are not independent seed plants, instead they are small structures found embedded within the sporophyte.

Cryptogams refer to the plants and fungi that do not reproduce by seeds. Besides these, the cryptogams are also known to reproduce by means of spores. All spore producing plants including mosses and ferns do not reproduce by seeds are hence, known as cryptogams.

The name horsetail, often used for the entire group, arose because the branched species somewhat resemble a horse's tail. 
Equisetum is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.
Equisetum is a "living fossil" as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall.

A cryptogam is a plant  that reproduces by spores and it is without flowers or seeds. Cryptogamae means hidden reproduction which refers to the fact that no seed is produced, thus cryptogams represent the non-seed bearing plants. Other names, such as "thallophytes", "lower plants", and "spore plants" are also occasionally used.

The phanerogams are the plants which can produce seeds. These are the plants which possess ovule where the fertilisation of male and female gametes takes place to form the zygote. The ovule is transformed into the seed after fertilisation. So, the seeds can be observed in the phanerogams. 

Ectophloic siphonostele, where the phloem is restricted to the outer surface of the xylem, is a characteristic feature found in Osmunda and Equisetum.

The plants exhibit the alternation of generations in their life cycle. The lower plants have a dependent sporophytic generation of the gametophyte. The first plants to develop as an independent sporophytic generation are the pteridophytes. These are the vascular plants which can survive in the terrestrial areas and has a independent diploid sporophytic stage. 

The cryptogams are flowerless (non-flowering) and seedless, spore-bearing plants. Phanerogams are flower bearing, seed producing tracheophytes. Bryophytes and pteridophytes come under cryptogams. 

Lycopodium is a genus of clubmosses which is also known as ground pines or creeping cedar. They are flowerless, vascular, terrestrial or epiphytic plants, with widely branched, erect, prostrate or creeping stems, with small, simple, needle-like or scale-like leaves that cover the stem and branches thickly. Their leaves contain a single, unbranched vascular strand and are microphylls by definition. The kidney-shaped or reniform spore-cases (sporangia) contain spores of one kind only (isosporous, homosporous) and are borne on the upper surface of the leaf blade of specialized leaves (sporophylls) arranged in a cone-like strobilus at the end of upright stems. The club-shaped appearance of these fertile stems gives the clubmosses their common name.

Vascular cryptogams are plants that possess vascular tissues but do not produce seeds, which defines the Pteridophytes. Equisetum is a well-known genus of Pteridophytes.

Equisetum is commonly referred to as the horse-tail plant due to the appearance of its jointed, ribbed stems.

Pteridophytes are vascular plants and have leaves (known as fronds), roots and sometimes true stems, and tree ferns have full trunks. For example, ferns, horsetails and clubmosses. Fronds in the largest species of ferns can reach some six meters in length. Many ferns from tropical rain forests are epiphytes, which means they only grow on other plant species. Their water comes from the damp air or from rainfall running down branches and tree trunks. There are also some purely aquatic ferns such as water fern or water velvet (Salvinia molesta) and mosquito ferns (Azolla species). Thallophytes and bryophytes are not differentiated into roots, stems and leaves. Hydrophytes are differentiated into roots, stems and leaves and bear flowers and seeds. 

The correct answer is 'Pteropsida'

Stele can be defined as the central core of the stem and root of a vascular plant, consisting of the vascular tissue (xylem and phloem) and associated supporting tissue. 

Sporocarp is a reproductive structure of some aquatic ferns like Marsilea. Sporocarps are functionally and developmentally modified leafwhich bears several sori. Each sori consists of sporangia of two types -mega sporangia producing simple large female megaspore and microsporangia producing many small male microspore.

A fern is a member of a group of approximately 12,000 species of vascular plants which reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular (i.e., having water-conducting vessels). They have stems and leaves, like other vascular plants. Most ferns have fiddleheads that expand into fronds, which are each delicately divided. Leptosporangiate ferns (sometimes called as true ferns) are by far the largest group, but ferns as defined here (ferns sensu lato) include horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. This group may be referred to as monilophytes. The term pteridophyte traditionally refers to ferns plus a few other seedless vascular plants.

The mature male gametophyte of Selaginella consists of 13 cells: 1 prothallial cell and 12 cells forming the antheridium (4 jacket cells, 4 primary androgonial cells, and 4 androcytes).

The heart-shaped prothallus is the characteristic feature of ferns and mainly belong to Polypodiaceae. They show polarity and dorsoventrally. The prothallus contains both the antheridia and archegonia which are embedded in the prothallus. Since it forms the male and female gametes the prothallus -is considered as the gametophyte.

Pteridophytes are cryptogamae, they are Non-flowering plants whereas phanerogams are flowering plants and are further classified as monocots and Dicots.

Araucaria imbricata is widely known by the common name Monkey's puzzle tree, a gymnosperm native to Chile.

Adiantum -Maiden Hair fern ( because of shining,smooth and blackish hair like petioles ).

Equisetum is characterized by its distinct jointed, ribbed, and green stems, which are capable of photosynthesis.

Lycopodium is a genus of club mosses that are homosporous, meaning they produce only one type of spore.

Lycopodium leaves are small, simple, and lack a ligule, making them eligulate. Ligulate leaves are characteristic of Selaginella.

In the life cycle of pteridophytes, the sporophyte is diploid and produces spores through meiosis within the sporangia.

Circinate vernation is characteristic feature of division filicophyta  (e.g.,Dryopteris) while Selaginella include in division lycophyta.

The sporangiophores of Equisetum are stalked, peltate (shield-shaped) structures arranged in whorls to form the strobilus.

The prothallus is the independent, heart-shaped, haploid gametophytic phase in the life cycle of pteridophytes.

The protocorm is a tuber-like structure that develops during the early stages of the development of the sporophyte in certain species of Lycopodium.

Amphiphloic siphonostele, where phloem is present on both the inner and outer sides of the xylem, is a characteristic feature of the stem of Marsilea.

Adiantum is commonly known as the maidenhair fern due to the delicate, dark, and hair-like appearance of its leaf stalks.

Cryptogams are plants that reproduce via spores and do not produce flowers or seeds, including algae, bryophytes, and pteridophytes.

Equisetum spores possess hygroscopic, ribbon-like structures called elaters that help in spore dispersal.

The vascular bundles of Equisetum stems contain carinal canals, which are formed by the breakdown of protoxylem elements.

Marsilea is an aquatic fern characterized by its leaves, which consist of four leaflets arranged in a clover-like pattern.

Equisetum plants are called scouring rushes because their stems contain significant deposits of silica, which makes them abrasive and useful for cleaning.

Archegoniophores are specialized stalked structures that bear archegonia in certain liverworts, most notably Marchantia, where both antheridiophores and archegoniophores are produced.

Adiantum is widely known as the maidenhair fern due to the appearance of its delicate, dark-colored leaf stalks.

Equisetum is commonly known as horse-tail due to its jointed, ribbed stems that resemble a horse's tail. It is a well-known genus of pteridophytes.

• Azolla is a genus of seven species of aquatic ferns belonging to family Salviniaceae. They are extremely reduced in form and specialized. They look similar to duckweeds and mosses.
  
• Salvinia, commonly known as Watermoss is a genus belonging to family Salviniaceae. It is a floating aquatic fern. Salvinia is related to other water ferns such as Azolla. 
  
• Marsilea, commonly known as water clover and four-leaf clover is a genus of approximately 65 species of aquatic ferns belonging to family Marsileaceae.
  
• Hence Azolla, Salvinia and marsilea are water ferns.
• So, the correct answer is 'All the above'.

Pteropsida (ferns) includes genera like Pteris, Adiantum, and Dryopteris. Psilotum belongs to Psilopsida, and Selaginella belongs to Lycopsida.

Vascular cryptogams are plants that possess vascular tissue (xylem and phloem) but reproduce via spores rather than seeds. Equisetum is a pteridophyte, which fits this definition, whereas Marchantia is a bryophyte (non-vascular) and Cedrus/Ginkgo are gymnosperms (seeded).

In pteridophytes, the main plant body is the sporophyte (2n). Meiosis or reduction division occurs during spore formation within the sporangia to produce haploid spores (n), which subsequently germinate into the gametophyte generation.

Ginkgo biloba is commonly known as the maidenhair tree because its fan-shaped leaves resemble the leaflets of the maidenhair fern (Adiantum). It is a unique living fossil gymnosperm.

Lycopodium has plectostele (4), Rhynia has haplostele (2), Marsilea has solenostele (3), and Polypodium has dictyostele (1).

Equisetum is known to have very small antheridia that produce a small number of sperms compared to other pteridophytes.

Adder's tongue is Ophioglossum (3), Horse tails is Equisetum (4), Club moss is Lycopodium (1), and Bog moss is Sphagnum (2).

In Lycopodium, the sporangia are borne on the adaxial surface of sporophylls, but they are often described as being in cones where the sporophylls are modified, though the statement 'cones without sporophylls' is technically a misnomer or refers to specific morphological interpretations.

All four statements are correct: Pteridophytes lack companion cells, xylem vessels are generally absent (except in some Gnetales/Selaginella), heterosporous ones have reduced gametophytes, and water is required for fertilization.

Selaginella is a heterosporous pteridophyte that produces two types of spores (microspores and megaspores) and possesses characteristic small leaves bearing a small ligule on their upper surface.

A vascular cryptogam is a plant with vascular tissue that reproduces by spores. Equisetum is a pteridophyte, which fits this category.

The root cell is diploid (2n=10). The indusium is part of the sporophyte (2n=10). The sperm mother cell is part of the gametophyte (n=5). The spore mother cell is part of the sporophyte (2n=10).

Adiantum, Equisetum, and Selaginella are all vascular cryptogams or pteridophytes. Riccia is a bryophyte (liverwort), making it the odd one out as it lacks vascular tissues.

The sporangiosphores of Equisetum are peltate (umbrella-like), stalked, and arranged in whorls on the strobili to carry multiple sporangia underneath.

Most species of Lycopodium produce only one type of spore, making them homosporous. In contrast, relatives like Selaginella are heterosporous.

The protocorm is a specialized tuberous, chlorophyllous structure formed during the early development of the young sporophyte in certain species of Lycopodium after the gametophytic stage.

Equisetum (horsetail) is well known for its jointed, ribbed, and green stems, which perform photosynthesis and have distinct nodes and internodes.

Pteridophytes comprise of a group of roughly 12,000 species of vascular plants that reproduce via spores and have neither seeds nor flowers, e.g., fern. They differ from mosses by being vascular (i.e., having water-conducting vessels). They have stems and leaves like other vascular plants. 

In Equisetum, the sporangiophores are stalked structures bearing sporangia underneath, forming a peltate (umbrella-like) disc shape arranged in whorls on the strobilus. Since all these structural characteristics are true, the correct choice is that all the above apply.

Bryophytes are known as the amphibians of the plant kingdom and they do not have any true roots stem or leaves.

Algae are chlorophyll bearing, simple, thyroid autotrophic and large aquatic organism. They have a non-vascular body.

The gametophyte of ferns and other pteridophytes is known as the prothallus. It is one cell thick, usually heart or kidney shaped and does not have roots, stems or leaves, but it does have rhizoids that anchor it to the soil and help with absorption. Both female (archegonium) and male (antheridium) sex organs are present in the prothallus. 

Each sperm of antherozoids is spirally coiled (2-3 coils) multiflagellated bearing 40-50 whiplash type flagella which are not applicable to fertilization in Dryopteris.

Heterospory is the production of spores of two different sizes and of two different developmental patterns -smaller male or microspores and larger female or megaspores. Heterospory is the most important evolutionary development in vascular plants because it has ultimately led to seed development, e.g., Selaginella, Salvinia, Azolla, etc.

(A) Psilopsida - Psilotum

Nepenthes is also known as the pitcher plant. It is an insectivorous plant. Psilotum is a pteridophyte and it is used for medicinal purpose. Aconitum is a medicinal plant. Rauwolfia is also a medicinal plant. 

ln pteridophytes, the diploid sporophyte is represented by a dominant, independent, photosynthetic, vascular plant body. It alternates with multicellular, saprophytic autotrophic, independent but short-lived haploid gametophyte.

The cryptogams are flowerless and seedless plants. They are simple plants including Algae, Mosses and Ferns. They do not produce flowers, fruits and seeds. Cryptogams are considered as lower plants. 

Sphenopsida (like Calamites) were dominant in the Carboniferous period, not the Jurassic.

The body of pteridophytes is differentiated into true stem, leaves and roots like higher plants. They possess well-developed vascular tissues like xylem and phloem for conduction of water and other substances from one part of plant body to another. While the body of thallophytes and bryophytes are not differentiated and lacks vascular system.

The Gnetophyta are a small group of vascular seed plants belonging to the phylum Gnetophyta.
The Gnetophyta include only three genera, Ephedra, Gnetum, and Welwitschia, each of which belongs to a separate family, in a single order, called as the Gnetales. 

Sphenopsida are represented today by the genus Equisetum, so they are not extinct.

Bryophytes are an informal group consisting of three divisions of non-vascular land plants: the liverworts, hornworts and mosses. They are characteristically limited in size and prefer moist habitats although they can survive in drier environments. A bryophyte spore germinates and produces an often algal-like mat, called a protonema (plural protonemata) and the leafy or thalloid stage of the gametophyte develops from the protonemal stage. The protonemata are almost always ephemeral but there are exceptions. Amongst the mosses there is a small number of species in which the protonemata are persistent and the leafy plants are ephemeral. The spore was haploid and so are the resulting protonema and the ensuing leafy or thalloid stages.

Pteris (a fern) and Cycas (a gymnosperm) both produce multiciliated antherozoids.

Most of the algae have dominant gametophyte generations. But in some species, the gametophytes and sporophytes are morphologically similar. An independent sporophyte is a dominant form in all clubmosses, horsetails, ferns, gymnosperms, and angiosperms that have survived to the present day. The gametophyte is dominant in the mosses, liverworts & hornworts only. In mosses, the gametophyte feeds its small attached offspring sporophyte. The mature sporophyte is composed of a "foot" that remains stuck in the gametophyte moss carpet. The sporophyte stands above the moss mat as a long stalk and a capsule that looks like a salt shaker at the tip.
The sporophyte is dominant in all other plants: the ferns, club mosses, horsetails, the gymnosperm (conifers, cycads, ginkgo), and the angiosperm.
In gymnosperm and angiosperm, the entire gametophyte generation is miniature and contained in the cones or the flowers.

Fern phloem lacks companion cells. Placenta in fern is the place of attachment of sporangia.
Companion cells occur only in angiosperms.
Companion cell is any of a number of specialized parenchyma cells adjacent to a sieve tube in the phloem of flowering plants, believed to regulate the flow of nutrients through the tube.

Pteridophyta is the primitive vascular plants. They are also called as vascular cryptogams. They are flowerless, seedless, spore-bearing vascular plants. In pteridophytes, the xylem mainly consists of tracheids and xylem parenchyma. Generally, vessels are absent but some primitive types of vessels are present in some of the species.

Ramenta is one of the thin, chaff like scales covering the shoots or leaves of certain ferns. Young leaves of fern are protected by ramenta.
Therefore, the correct answer is option B.

Pteridophytes:
1. Members of this group are most primitive living vascular plants.
2. The main plant body is a sporophyte. It is differentiated into root, stem and leaves.
3. Plants (sporophyte) reproduce by spores formed in sporangia. Sporangia develop either on the ventral surface or in the axil of leaves.
4. Plants may be homosporous or heterosporous. The development of sporangium may be of eusporangiate (when developing from a group of initials) or leptosporangiate. (When developing from a single initial) type.
5. Spores develop into a multi-cellular gametophytic body called prothallus- a thalloid structure. It is independent and chlorophyllous. It bears male reproductive organs called antheridia and female reproductive organs called archegonia. Reproductive organs are multicellular and jacketed.
6. Water is essential to effect fertilization as male reproductive units are flagellated and motile.
7. Seed formation never takes place in living pteridophytes.
8. An embryo develops in situ after fertilization and the sporophyte remains attached to the gametophyte till the development of root.
9. Plants show clear alternation of generations. The sporophyte and gametophyte are independent of each other.

Pteridophytes or Pteridophyta are vascular plants meaning that they contain vascular systems for the transport of water and food material.These vascular systems are xylem and phloem. They reproduce bt spores. They are flowerless and seedless plants and hence they are also called as vascular cryptogams. 

Pteridophytes are vascular plants which have leaves (known as fronds), roots and sometimes true stems, and tree ferns have full trunks. For example, ferns, horsetails and clubmosses. Fronds in the largest species of ferns can reach some six meters in length. Many ferns from tropical rain forests are epiphytes, which means they only grow on other plant species. Their water comes from the damp air or from rainfall running down branches and tree trunks. There are also some purely aquatic ferns such as water fern or water velvet (Salvinia molesta) and mosquito ferns (Azolla species). 

Pteridophytes are seedless ferns. They use sexual and asexual mode of reproduction. Spores produced by pteridophytes that help in sexual reproduction. These spores are carried long distances for pollination by abiotic factors like wind, water, etc. Once the spore reaches its destination, it releases the male gametes into the female reproductive system and merges with the female gamete. After successful divisions, it germinates to become prothallus, i.e, the young ones of pteridophytes. So, the correct answer is option B.

Pteridophyta is the only division of sub-kingdom cryptogamae that can reproduce both, sexually by formation of spores as well as sexually by formation of gametes.

Pteridophyta are multicellular, autotrophic plants, they can reproduce asexually as well as sexually. They reproduce asexually by formation of spores and sexually by the formation of gametes.

Heterospory is considered a crucial evolutionary step toward the seed habit, as it leads to the retention of the megaspore and the development of the female gametophyte within the parent plant.

Pteridophytes are called vascular cryptogams because they contain vascular tissues (xylem and phloem) but reproduce via spores rather than seeds.

Equisetum is a genus of Pteridophyta division. They are called as cryptogam. Vascular cryptogamic plants are those plants which have vascular system and do not have seeds. Equisetum is a vascular plant bearing hidden seeds.

Fern stems are often called rhizomes, but this term refers to those with a long-creeping or climbing habit. If the stem is short and compact and radially symmetric, either erect, prostrate or ascending then it is called a caudex or rootstock. In some cases, the caudex is erect and tree-like with an apical radial tuft of leaves in which case it is often called a trunk. The rhizomes of ferns are very rarely naked and usually have some form of covering, especially on their growing tips, to provide protection from the extremes of temperature, desiccation, predation and physical abrasion. The rhizome have sieve tubes but there are no vessels. 

(A) Pteris - Pteridophyte

Only statement (b) is correct: Ginkgo male gametophytes are not independent. (a) is false because Equisetum gametophytes are independent. (c) is false because Polytrichum sporophytes are more complex than Riccia. (d) is false because Volvox reproduction is oogamous. (e) is false because slime mould spores have cellulose cell walls.

Adiantum, Lycopodium, Marsilea and Selaginella are multicellular autotrophic plants, they belong to kingdom plantae, sub-kingdom: cryptogamae and division pteridophyta.

Angiosperms are flowering plants. Gymnosperms are non-flowering plants. They are seedless plants. The main feature which is common to both of them is the presence of tracheids. Tracheids are vessel elements in plants. They help in the movement of water and minerals across the plants. 

Tracheophytes are plants having dignified and developed vascular tissue for conducting water and minerals. Spermatophytes are plants that produce seeds. All tracheophytes are not spermatophytes (pteridophytes aren't spermatophytes). Phanerogams is however, an alternative them for spermatophytes.

Cryptogams are plant or plant-like orgnaisms which reproduce by spores. Examples include algae, lichens, liverworts, mosses ferns. They do not have true flowers or seeds. They include thallophyta, bryophyta and pteridophyta. In these, reproductive organs are hidden.

Vascular tissues are also known as conductive tissue, they help to conduct water and other substances from one part of the plant body to another. For example, ferns contain two types of vascular tissue, xylem and phloem, which move nutrients throughout the plant and allow them to grow tall. 

Marsilea is a water fern that produces specialized, hard, bean-shaped reproductive structures known as sporocarps. These structures contain the sporangia.

• Homosporous plants are those which produce spores of one kind only that are not differentiated by sex. The spores of homosporous plants grow into bisexual gametophytes, producing both male and female gametes.
• Lycopodium is a genus of clubmosses, belonging to the family Lycopodiaceae. It contains kidney-shaped or reniform sporangia which contain spores of one kind only (homosporous) and are borne on the upper surface of the leaf blade of specialized leaves (sporophylls).
• Equisetum is the only living genus belonging to the family Equisetaceae. They are mostly homosporous, in which spores are borne under sporangiophores.

The sporocarp is a characteristic reproductive structure found in the genus Marsilea, which is a heterosporous aquatic fern.

Most premitive vascular plants are pteridophytes.
Cycas belongs to gymnosperms. Gymnosperms have a well-differentiated plant body with vascular tissues. They produce naked seeds. Hence, option A is incorrect. 
Moss belongs to bryophytes. Bryophytes have a well-differentiated plant body with stem and leaf-like structures. But there is no specialized vascular or mechanical tissue. Therefore, option C is incorrect. 
Brown algae belong to thallophytes. Thallophytes do not have well-differentiated plant body and vascular tissues. Therefore, option D is incorrect. 
Ferns belong to pteridophytes. Pteridophytes have a well-differentiated plant body with vascular tissues. Therefore, option B is correct.