Some liverworts reproduce asexually by fragmentation or by forming gemmae (green, multicellular asexual buds). These are held in gemma cups and dispersed by rain. Each gemma germinates to form a new individual.

Carrageen is extracted from red algae such as Chondrus. It is a polysaccharide known for its gelling and stabilizing properties used in milk products.

Chlorella and Spirulina are unicellular algae rich in protein and used as food supplements. Others like Gelidium, Gracilaria, Laminaria, and Sargassum are multicellular.

Phycoerythrin is the major pigment in red algae (Rhodophyceae). Red algae possess chlorophyll-a, carotenoids, and phycobilins (including phycoerythrin).

Polysiphonia is a red algae with oogamous reproduction. Male gametes are non-flagellate. Hence, 'Uniflagellate gametes – Polysiphonia' is incorrect.

Volvox is a freshwater green colonial alga forming a spherical colony of 500–60,000 cells embedded in mucilage, called a coenobium.

Zygotic meiosis occurs in the haplontic life cycle of algae like Chlamydomonas. Meiosis takes place in the zygote, resulting in haploid spores that form haploid plants.

Algin is obtained from brown algae (e.g., Laminaria), while carrageenan is obtained from red algae (e.g., Chondrus). Hence, only statement (b) is wrong.

Mucor belongs to class Zygomycetes and has non-motile, non-flagellated gametes. Hence, statement (b) is incorrect.

Peat is mainly an accumulation of partially decayed vegetation or organic matter. Sphagnum accumulations can store large quantities of water, contributing to peat formation.

Chlorella is a potential food source because it is high in protein and other essential nutrients. When dried, it contains about 45% protein, 20% fat, 20% carbohydrate, 5% fibre, and 10% minerals and vitamins.

Both antheridium and oogonium are the male and the female reproductive structures respectively. They have sterile jackets on their surface. In Chara, the globule (antheridium) is present on the lower side, while the nucule (oogonium) is present on the upper side of the sterile vegetative (leaf-like) structure.

Spirogyra reproduces sexually by conjugation (isogamy) where non-flagellated but morphologically similar gametes fuse. One filament acts as the male, the other as female.

Multicellular fungi, filamentous algae and protonema of mosses all show multiplication by fragmentation, a form of asexual reproduction.

Statement (c) is wrong because in oomycetes (water moulds, white rusts and downy mildews), the female gamete is large and non-motile while the male gamete is small and motile. Isogametes occur in Ulothrix, Chlamydomonas, Spirogyra, etc. Anisogametes occur in Chlamydomonas (one gamete is larger and non-motile, the other smaller and motile). Oogamy occurs in Chlamydomonas, Fucus, Chara, Volvox, etc.

In Marchantia, a bryophyte, the archegonia (female sex organs) are borne on special branches called archegoniophores or female receptacles. Each has rows of archegonia protected by an involucre or perichaetium.

In Sphagnum, male and female gametophytes are independent and free-living. In bryophytes, the most conspicuous phase in the life cycle is the gametophyte, which is independent and responsible for reproduction.

Algae have cell wall made up of cellulose, galactans and mannans. Like plants, algal cell walls contain polysaccharides such as cellulose or a variety of glycoproteins or both. The inclusion of additional polysaccharides like mannan helps in algal classification.

Fucus (brown algae, Phaeophyceae) stores food in the form of laminarin, mannitol and oil. Chara (green algae, Chlorophyceae) stores starch and oil, while Porphyra and Gracilaria (red algae, Rhodophyceae) store floridean starch and galactan-sulfate polymers.

Elaters are hygroscopic structures in some liverworts that help in the dispersal of spores.

Types of pigments present in algal cells are the most important character used for classification of algae.

Sphagnum, commonly called bog moss or peat moss, is hygroscopic and has a remarkable water-holding capacity. Hence, it is used for packing flowers, plants, bulbs, and seedlings for transport.

Members of Rhodophyceae (red algae) contain chlorophyll-a, d, r-phycoerythrin, r-phycocyanin, and carotene pigments. Green algae (Chlorophyceae) have chlorophyll-a, b; Bacillariophyceae (diatoms) have chlorophyll-a, c; and Cyanophyceae have chlorophyll-a and phycobilins.

Bryophytes are non-vascular cryptogams, their main plant body is gametophytic (haploid) which is a thalloid structure. It contains chlorophyll for photosynthesis and bears archegonia as female sex organs.

Bryophyta is a group of thalloid, non-vascular, cryptogams which have gametophytic (haploid phase) as dominant phase. It bears diploid sporophytic phase which takes food from gametophytic phase, thus behaves as parasite on gametophyte.

Though many liverworts are dichotomously branched but some of the leafy liverworts are not. However, Marchantia is a liverwort which is dichotomously branched.

The antherozoids of Funaria are spirally coiled and biflagellated, bearing two equal flagella at the anterior end.

The antherozoids (sperms) of bryophytes are flagellated (motile) and need a film of water to swim through for reaching the archegonium. Bryophyta is a group of cryptogams whose main plant body is gametophytic (haploid) bearing sex organs.

Ulothrix is a freshwater filamentous green alga found in cold water. It reproduces sexually by isogamy between morphologically similar motile flagellated gametes from different filaments.

In pteridophytes and gymnosperms, gametophyte generation is reduced and sporophyte is well-developed. In bryophytes, gametophyte constitutes the main generation but in mosses, e.g., Funaria, it is foliose with multicellular rhizoids.

Archegonia is female sex organ in bryophytes. It is flask-shaped multicellular organ composed of a neck with sterile cells and a swollen venter that encloses a large egg cell and a smaller venter canal cell (VCC).

Dried Chlorella pyrenoidosa contains approximately 50–55% crude protein, which is higher than that in dried beef, soyabean meal, and dried yeast. Hence, Chlorella is considered a protein-rich alga.

In addition to chlorophyll-a, brown algae possess special carotenoids and fucoxanthin. It is due to the presence of fucoxanthin (brown pigment) that these algae appear brown. Phycocyanin and phycoerythrin are phycobilins found in red and blue-green algae respectively.

Ulothrix belongs to green algae. Sexual reproduction in Ulothrix takes place by the union of isogametes which are motile, biflagellate, and morphologically similar gametes. Approximately 8–32 isogametes are produced from a mother cell. Two gametes from different filaments fuse to form a diploid zygote.

In Marchantia, capsule (the part of sporophyte) contains elaters (2n) and spores (n) in tetrads. Elaters are diploid, spindle-shaped, hygroscopic elongated structures with two spiral bands which help in spore dispersal on maturity.

Blue-green algae (cyanobacteria) are prokaryotic organisms. They are Gram-negative, aerobic, photoautotrophic, nitrogen-fixing thallophytes. They lack a true nucleus, plastids, flagella, and membrane-bound organelles. Their ribosomes are of the 70S type.

Funaria (green moss) and other bryophytes show alternation of generation with haploid gametophytic and diploid sporophytic phases. The plant body represents the gametophytic phase, while the sporophyte is dependent and differentiated into foot, seta and capsule.

Ulothrix has three types of cells: apical green dome-shaped, intercalary green, and basal non-green cell (holdfast). The holdfast is used for attachment and shows the beginning of division of labour in the filament.

Agar is a gelatinous, sulphated, tasteless mucopolysaccharide obtained from the middle lamella of red algae such as Gracilaria, Gelidium, and Gigartina. It is used as a solidifying agent in culture media, and as a thickener in jams, jellies, and ice creams.

Spirogyra is a filamentous green freshwater alga that cannot fix nitrogen. Blue-green algae such as Nostoc and Anabaena are nitrogen-fixing cyanobacteria, while Azotobacter is a free-living nitrogen fixer.

In Chlorophyceae, sexual reproduction occurs by all three methods — isogamy, anisogamy, and oogamy. Isogamy involves fusion of similar gametes, anisogamy involves fusion of morphologically different gametes, and oogamy involves fusion between a motile male gamete and a non-motile female gamete.

Pyrenoid is a seat of synthesis and storage of starch present in the chloroplast of algae. A pyrenoid has a core of protein around which starch is deposited as layers.

In Chlamydomonas, the chloroplast is single and cup-shaped. It contains chlorophyll-a and chlorophyll-b pigments that impart green colour to the alga. The number and shape of chloroplasts vary among different algal classes.

Bryophytes have thalloid body attached by rhizoids, lack vascular tissues, and require water for fertilisation. They exhibit alternation of generations between gametophyte and sporophyte producing spores and embryos.

Bryophytes are called amphibians of the plant kingdom because they are the first land plants that need a layer of water for fertilisation due to motile male gametes.

Of the given options, moss has the largest gametophyte. It gets reduced in the order Selaginella → Cycas → Angiosperms. Gametophyte begins with a haploid spore and ends with gametes.

Zygospore (zygote) is the fusion product of two gametes and represents a resting stage formed after flagella withdrawal and thick wall formation. In Spirogyra, sexual reproduction occurs through conjugation producing a diploid zygospore with three-layered wall and abundant food reserves.

Peristome functions in spore dispersal. It consists of rings of teeth-like projections at the rim of the capsule. In Funaria, peristome has 32 teeth arranged in two rings of 16 each—outer exostome and inner endostome.

The capsule of Funaria is divided into operculum (top lid), theca (middle fertile part), and apophysis (sterile, solid basal portion of the capsule having chloroplasts).

In Pteris, during fertilisation, sperms are attracted by chemicals diffusing from mucilage secreted by open necks of archegonia. This chemotactic attraction ensures species-specific fertilisation.

Acetabularia is the largest uninucleated green marine alga, popularly called mermaid’s wine glass or umbrella plant. It has a cap, stalk, and rhizoidal base with the nucleus in the base. J. Hammerling’s experiments proved the role of the nucleus in heredity, growth, and differentiation.

In Chlamydomonas, hologamy involves the fusion of two young individuals directly, e.g., C. snowiae. Isogamy involves fusion of gametes that are similar in size and structure, e.g., C. euganetos.

Heterospory is the production of spores of two different sizes and of two different developmental patterns. It is the most important evolutionary development in the vascular plants because it has ultimately lead to seed development, which is seen in Selaginella, Salvinia, Azolla, etc.

Metagenesis in an organism refers to the reproduction characterised by the alternation of a sexual generation and a generation that reproduces asexually, i.e. alternation of generations.

Ectocarpus and Fucus respectively show haplodiplontic and diplontic life cycle. In Ectocarpus, sporic meiosis occurs and haploid biflagellate meiozoospores are formed. They germinate to produce gametophytic thalli. The gametophytes liberate gametes, which fuse to form diploid zygote, which gives rise to a diploid plant.

A. Peritrichous flagella – Escherichia coli (flagella all over the body) B. Living fossil – Ginkgo biloba (maiden hair tree) C. Rhizophore – Selaginella (a pteridophyte) D. Smallest flowering plant – Wolffia E. Largest perennial algae – Macrocystis

A few plants, (e.g. Rafflesia) are parasitic. Some angiosperm genera are vesselless. Secondary growth does not take place in a large variety of angiosperms. However, double fertilisation is met with amongst all angiosperms. In this one male gamete fuses with egg nucleus (n). This is known as syngamy and the second male gamete fuses with the secondary nucleus or polar nuclei (2n). This is known as triple fusion. Together these syngamy and triple fusion is known as double fertilisation.

Angiosperms are well adapted to terrestrial life and occur in diverse habitats like cold tundra to hot tropical and even desert areas. They also thrive well in aquatic habitat. Hence, they being the most successful, to have dominated the land flora.

The conifers (gymnosperm) differ from the grasses (angiosperm) in the formation of endosperm before fertilisation. Infact, in gymnosperms, the endosperm is a haploid tissue as it formed before fertilisation, while in angiosperms, endosperm is formed after fertilisation as a result of triple fusion or double fertilisation, thus, it is a triploid tissue. In both conifers and grasses seeds are produced from ovules. Xylem tracheids are present in both conifers and grasses. Pollen tubes are also formed in both conifers and grasses.

As we proceed from thallophyta to angiosperms, there is gradual reduction in gametophyte with reduced size of sex organs. From thallophyta to angiosperms, there is progressive elaboration of sporophytes.

Lilium (angiosperm) possesses the male gametophyte with least number of cells. The number of cells in male gametophyte shows the pattern of reduction from bryophytes to angiosperms. In angiosperms, it is reduced to about 2-3 celled and called as pollen grains. The number of cells in male gametophyte decreases in the following order Funaria > Pteris > Pinus > Lilium.

The most common type of female gametophyte (embryo sac) in angiosperms is the monosporic embryo sac in which the embryo sac develops from a single functional megaspore (n) while the other three megaspores degenerate. The functional megaspore undergoes three sequential mitotic divisions and gives rise to 8-nucleate and 7-celled mature embryo sac.

Male and female gametophyte do not have an independent free-living existence in gymnosperms and angiosperms. In them they remains within the sporangia retained on the sporophytes. The pollen grain is released from the microsporangium and are carried in air currents and come in contact with the opening of the ovules borne on megasporophylls. The pollen tube carrying the male gametes grows towards archegonia in the ovules and discharge their contents near the mouth of the archegonia.

In gymnosperms, e.g. Pinus, Cycas, endosperm develops before fertilisation and is haploid in nature. In angiosperms, endosperm is triploid (3n) and formed after double fertilisation.

In gymnosperms, the megaspore (haploid) is first cell of female gametophyte and undergoes repeated divisions to form a multicellular female gametophyte, which because of abundant food reserves, serves as endosperm. So, being produced before fertilisation, endosperm is haploid in gymnosperms. Microspores or pollen grains are the first cell of the male gametophyte and are haploid in nature.

Pinus roxburghi is a source of resin and terpentine, obtained after distillation. Terpentine is utilised in varnishes and paints.

In gymnosperms (Pinus) both the pollen grains and endosperm are haploid structure, formed before fertilisation. If the pollen grain has haploid number of chromosome equal to 6, then its endosperm will also have the same number of chromosome, i.e. 6.

Gymnosperms (Gk Gymno=naked ; sperma-seed) are commonly known as naked seed plants because their ovules (which later become seeds) are not covered and lie naked on the surfaces of specialised leaves called megasporophylls or ovuliferous scales, arranged into cones, flowers are absent; seed may have two, (e.g. Cycas) or more (e.g. Pinus) cotyledons.

From the evolutionary point of view, the given options can be arranged as Chlamydomonas, Funaria, Selaginella, and Pinus. Pinus, i.e. gymnosperms are the most evolved seed bearing phanerogamic vascular sporophytic plants, after angiosperms (most advanced group of plants). Pteridophytes (e.g. Selaginella) are spore bearing non-seeded vascular cryptogams. Algae, bryophytes and pteridophytes resemble each other in dependence on water for fertilisation.

Gymnosperms, (e.g. Pinus) are commonly called as naked seeded plants since their ovules (which later become seed) are not covered and lie naked on the surfaces of specialised leaves (megasporophylls or ovuliferous scales) arranged into cones. Thus, gymnosperms are also known as seeded plants without flowers or phanerogams without ovary. In contrast, angiosperms are seed bearing, flowering vascular plants in which seeds are enclosed in fruits, and are called as phanerogams with ovary or seeded flowering plants.

The wings of seed of Pinus is thin, membranous diploid and develops jointly from the basal upper surface (adaxial) of ovuliferous scale and outer layer of integument of the ovule.

The tendency towards seed formation is called seed habit. It was developed in fossil gymnosperm of group Cycadofilicales (pteridosperms), i.e. seed ferns, e.g. Lyginopteris which bears characters of cycads and ferns both. Seed habit is shown by few pteridophytes like Selaginella, Marselia, Isoetes, etc. which exhibit heterospory.

Statement (c) is incorrect regarding Cycas as Vessels are absent from the xylem of all gymnosperms (except Gnetales). Cycas belongs to Cycadales (not Gnetales).

Cycas is a gymnospermic plant. It has the biggest sperms (antherozoids) and ovules in the plant world.

Pteridophytes and gymnosperms do have vascular tissues. However, gymnosperms bear seeds while pteridophytes not bear seeds. Algae and bryophytes do not possess vascular tissues.

Cycas with largest antherozoids and ovule and the largest plant Sequoia belong to gymnosperms. Gymnosperm is a group of naked seeded plants, i.e. their ovules are not enclosed by ovary walls. Ovules of gymnosperms are directly borne on the megasporophyll.

Gymnosperms (Gk. gymnos-naked; sperma-seed e.g. naked seed plants) is a group of phanerogams which have naked ovules, i.e. structure (ovules) that eventually become the seeds after fertilisation and not completely enclosed by the tissues of the parent individual.

Pinus is a gymnospermic plant. Ovules of Pinus are uncovered which lie on the megasporophyll, hence, these plants do not have flowers. However, it produces seeds (from ovule after fertilisation) like other three plants mentioned, all of which are angiosperms.

Ginkgo is a gymnospermic plant so it comes before angiospermic plant, Pisum (pea). Rhizopus is a fungus and Triticum (wheat) is an angiospermic plant. Option (c) has both angiospermic plants and option (d) has both gymnospermic plants.

Roots are not the common structure in Funaria and Selaginella. Funaria (moss) and Selaginella (pteridophytes) can be related with the presence of archegonium, embryo, flagellated sperms. In Funaria, the plant is attached to the substratum by means of root-like structures called rhizoids, which are multicellular, branched, have oblique cross wall. In Selaginella, special leafless positively geotropic structures called rhizophores arise from the stem at the point of branching. Rhizophore resembles the stem in some characters and roots in other characters and was regarded as organ-sui-genesis (organ of independent origin).

Archegonium is the flask-shaped female reproductive body of bryophytes and pteridophytes. Archegonium usually consists of a tubular neck and a swollen venter. Neck is made up of 4-6 vertical row of cells and encloses 6-10 neck canal cells in bryophytes and 4 vertical rows in pteridophytes enclosing 1-4 neck canal cells. Venter has 1-2 layer but it is wall-less in pteridophytes.

Adiantum is called walking fern. The tips of its leaves, on coming in contact with the soil, gives out adventitious roots which in turn produce new leaves and develop into new plants.

In the ferns sporangium is a diploid structure. It bears diploid spore mother cells which undergo meiosis and produce haploid spores. Each spore contains an outer thick brown wall called exine and a thin inner wall called intine. Spore is the first cell of gametophyte. On germination, it gives rise to a haploid gametophytic stage.

Fern is a pteridophyte and Funaria is a bryophyte, both these produce spores but not seeds. Phanerogams is a group of plants which produce seeds and flowers. It includes gymnospermic and angiospermic plants. While cryptogams is another group of plants which do not produce seeds and flowers, e.g. algae, fungi, bryophytes and pteridophytes.

Adiantum is also called walking fern. In Adiantum the tips of the leaves, on coming in contact with the soil, give out adventitious roots which, in turn, produce new leaves and develop into new plants.

From the following Salvinia is heterosporous. Heterospory is the production of spores of two different sizes and two different developmental patterns. Small spores are called microspores and larger as megaspore. Microspores germinate to produce the male gametophyte or microgametophyte that bear male sex organs while, megaspore germinates to form female gametophyte or megagametophyte that bears archegonia or female sex organs. It is most important evolutionary development in the vascular plants because it has ultimately lead to seed development, e.g. Selaginella, Marselia, Salvinia, Azolla, Isoetes. Dryopteris is homosporous and 32–64 haploid spores are produced in each sporangium. Adiantum is also homosporous. The spores are the pioneer structures of the gametophytic generation.

Cedrus is a gymnosperm in which main plant body is a sporophyte on which reduced type of gametophytes are formed. In Pteris (also Dryopteris) the spore germinates to produce the prothallus. The prothallus is a small, green flat, surface loving, thallus-like object. It is monoecious and bears sex organs on the ventral side. The antheridia (male sex organs) arise among the rhizoids towards the posterior side of the prothallus and are emergent. The archegonia develop in central cushion behind the apical notch. In these plants male and female, gametophytes do have free living independent existence. All species of Polytrichum are dioecious. The antheridia and archegonia are borne on different gametophore. The plant body is an erect leafy shoot but is not the entire gametophyte. The leafy shoot arise from protonema (the juvenile stage). The leafy gametophore of Funaria reproduces sexually by formation of antheridia and archegonia. The antheridia are formed at the summit of a relatively small, thin, leafy shoot, which develops first. The female branch arises later as a lateral outgrowth from the base of parent male shoot.

Pteridophytes are also called vascular cryptogams as these have a well developed vascular system but are non-flowering plants. e.g. Equisetum.

Origin of seed habit can be traced in pteridophytes. Some pteridophytes like Selaginella and Salvinia are heterosporous as they produce two kinds of spores micro (small) spores and macro (large) spores, which germinate and give rise to male and female gametophyte respectively. The female gametophyte in these plants are retained on the parent sporophytes for variable periods. The development of the zygote into young embryos takes place within the female gametophyte. This event is the precursor to the seed habit and considered to an important step in evolution.

In several primitive simple plants–like algae, bryophytes and pteridophytes, water is the medium through which male gametes are transferred to the female reproductive organ or gamete to bring about fertilisation.

Roots are not common in Funaria and Selaginella. Funaria (a moss) has multicellular branched rhizoids, while Selaginella (a pteridophyte) has true roots or rhizophores that function like roots.

Archegonium is the flask-shaped female reproductive organ of bryophytes and pteridophytes. It has a neck with 4–6 rows of neck canal cells and a swollen venter containing the egg.

Adiantum is called the walking fern because its leaf tips, on coming into contact with soil, give rise to new plants through adventitious roots and leaves.

In ferns, meiosis occurs in the diploid spore mother cells present in the sporangium, resulting in the formation of haploid spores. Each spore germinates to give rise to a gametophyte.

Fern (a pteridophyte) and Funaria (a bryophyte) produce spores but not seeds. Phanerogams produce seeds and flowers, while cryptogams (algae, fungi, bryophytes, pteridophytes) do not.

Adiantum, known as the walking fern, propagates vegetatively by its leaf tips. When leaf tips touch the soil, they give out adventitious roots which produce new plants.

Salvinia is heterosporous, producing two types of spores – microspores and megaspores. Microspores germinate to produce male gametophytes, while megaspores form female gametophytes. This is an important evolutionary step leading to seed development. Dryopteris and Adiantum are homosporous.

In Cedrus (a gymnosperm), the main plant body is a sporophyte on which reduced gametophytes are formed. In contrast, in Pteris, Funaria and Polytrichum, male and female gametophytes are free-living and independent.

Pteridophytes are also called vascular cryptogams as they possess a well-developed vascular system but are non-flowering plants, e.g., Equisetum.

Origin of seed habit can be traced in pteridophytes. Some pteridophytes like Selaginella and Salvinia are heterosporous as they produce two kinds of spores – microspores and megaspores. The female gametophyte is retained on the parent sporophyte, and zygote development occurs within it, marking the evolutionary beginning of the seed habit.

In several primitive simple plants like algae, bryophytes and pteridophytes, water is the medium through which male gametes are transferred to the female reproductive organ or gamete to bring about fertilisation.

Protonema represents the juvenile stage of moss (Funaria). It is a green filamentous structure formed by spore germination under favourable conditions and develops rhizoids and buds that grow into new gametophores.

The main plant body of bryophytes is gametophytic and independent. The sporophyte is differentiated into foot, seta and capsule, and remains attached and dependent on the gametophyte.

In the prothallus of a vascular cryptogam, the antherozoids and eggs mature at different times, which prevents self-fertilisation and promotes cross-fertilisation.

In Chlamydomonas, the plant body is haploid and represents gametophyte. It reproduces asexually through zoospores and sexually through gametes. Gametes fuse to produce a diploid zygote representing the sporophytic generation. The zygote secretes a wall around it to become a resting zygospore (diploid).

In Ulothrix and Spirogyra, meiosis occurs during zygospore germination. The zygote (2n) undergoes zygotic meiosis to form haploid spores that germinate into new filaments of (+) or (–) strains.

In Spirogyra, sexual reproduction involves the fusion of two morphologically identical but physiologically dissimilar gametes (anisogametes). The active gamete acts as male, and the passive one as female — representing physiological differentiation.

Ectocarpus is a cosmopolitan marine brown seaweed. Mannitol is stored as a food reserve in Ectocarpus. Other options can be explained as: ● Gracilaria is a red algae that stores floridean starch as reserve food. ● In Volvox (green algae), stored food material is starch and sometimes oil droplets. ● Ulothrix is a filamentous green algae where starch is the reserve food.