the spores of bryophytes are haploidthe spores of bryophytes are haploid

2017, Villarreal and Renner 2013). Nature 450:238241, Tanurdzic M, Banks JA (2004) Sex-determining mechanisms in land plants. During the sporophyte stage, the plant produces spores with diploid or two sets of chromosomes (2n) by the process of mitosis. What are the three classes of bryophytes? The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations. The author declares no competing interests. Diploid sporophyte is typically not If the neo-sex chromosome resulting from fusions in the moss ancestor initially had a greatly expanded recombining region carrying the former autosomes genes. The calyptra buds to form a mature gametophyte. The Y population is isolated from the (larger) X population, allowing greater effects of genetic drift on the Y than other chromosomes, which also contributes to processes causing genetic degeneration, as reviewed by Bachtrog (2008). The sporophyte is the first phase of a plant's life cycle and is a diploid plant that produces spores; the second phase is a haploid gametophyte plant that produces eggs and sperm. In: Greenwood PJ, Slatkin (eds), EvolutionEssays in Honour of John Maynard Smith Cambridge University Press, Cambridge, 237268, Gao B, Chen M, Li X, Liang Y, Zhang D, Wood A et al. for The plant is called a thallus, they .. Plantlife can be studied at a variety of levels, from the molecular, genetic and biochemical level through organelles, cells, tissues, organs, individuals, plant populations, and communities of plants. Like other bryophytes, Marchantia sporophytes are not the predominant stage in their life cycle. Non-vascular plants are those which do not possess a vascular system i.e., xylem and phloem. Bull therefore predicted that, although both sex chromosomes should degenerate to similar extents, degeneration should be minor on both, and neither should involve losses of many genes. To obtain Sphagnum is a bryophyte moss that shows alternation of generation. Cytogenetics Cell Genet 92:7479, Westergaard M (1958) The mechanism of sex determination in dioecious plants. Following fertilisation, the zygote develops into embryo and the ovules into seeds. They generally lack lignin and do not have actual tracheids (xylem cells specialized for water conduction). respectively. 2011, Westergaard 1958). Ltd.: All rights reserved. The gymnosperms produce microspores and megaspores which are produced in microsporangia and megasporangia borne on the sporophylls. Produced by the process of spore germination, 4. 6th edition. feature of bryophytes In bryophyte: Reproduction and life cycle Mature bryophytes have a single sporangium (spore-producing structure) on each sporophyte. It produces haploid spores. The U-linked female-determiner has recently been identified, with a V-linked copy that appears to be essential for male reproduction (Iwasaki et al. The dominant phase of the moss life cycle is the gametophyte (haploid). Cladocarpic antherozoids. disintegrate, opening the neck for the entrance of the antherozoids. The peristomate or true mosses (Superclass V) on the basis of position of the perichaetia and C. People who follow FIRE plan to retire much earlier than the traditional retirement age of 65 by spending up to 70% of their income on traveling while still in the full-time workforce. Genetics 197:865883, Article Mosses absorb water and nutrients carried by the rain and do not need soil because they do not derive much nutrition from the soil. Liverwort plants can also reproduce asexually, by the breaking of branches or the spreading of leaf fragments called gemmae. separately.They are not According to the passage, what is the difference between the adherents of Fat FIRE and Lean FIRE when it comes to their standards of living? The gametophytes grow as flat thalli on the soil with embedded male and female gametangia. As the name suggests, seedless vascular plants possess a vascular system however, such plants do not produce seeds. The ovum remains in the archegonium and spermatozoids swim to it by Plants with macroscopic predominant sporophyte stage, 2001-2023 BiologyOnline. Genetic mapping identified PARs at both ends of the C. purpureus U and V chromosomes (McDaniel et al. They include the mosses, the liverworts, and the hornworts. Overall, therefore, many more bryophyte than angiosperm species are available for studying sex chromosomes. Q. If none follows select option 5 as your answer. They differ from the other vascular plants in producing seeds that germinate into a new plant. Spore Germination and Protonemata :- Moss life cycle begins when haploid spores are released What is a sporophyte? The content on this website is for information only. Ecology 72:597608, Institute of Evolutionary Biology, School of Biological Sciences, Ashworth Lab, University of Edinburgh, Edinburgh, UK, You can also search for this author in Mosses have simple conductive cells and are attached to the substrate by rhizoids. Hence, the plant life cycle alternates between the gametophyte (sexual) stage and the sporophyte (asexual) stage. Spores of 1 sporophyte from a mating of this type yielded 1 triploid gameto- phyte (with 27 chromosomes), 1 hypotriploid (with 24), 9 diploid (with 18), 2 hyperhaploid (with 10), 2 haploid (with 9). Fungi and algae are common examples that exhibit alternation of generation. History For All PSC Exams (Beat the Unbeatable): Mini Mock Test, Copyright 2014-2022 Testbook Edu Solutions Pvt. (iii) Sex-organs are unicellular and non-jacketed. It is not intended to provide medical, legal, or any other professional advice. The bryophytes are divided into liverworts and mosses. The teeth are attached to a thick-walled annulus around Most of the autosomes were found as homeologous pairs, as expected after a WGD event. CAS This branching filament is Publishers note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Any information here should not be considered absolutely correct, complete, and up-to-date. The sporophylls - microsporophylls and megasporophylls - are arranged spirally on axis to form male and female cones, respectively. The phloem-like sugar-and-amino-acid-conducting tissue is called As for primitive plants like bryophytes, the gametophyte stage is the dominant phase in the plant life cycle. spores in place. All Rights Reserved, Table 1: Difference between Gametophytes and Sporophytes, Meiosis and Alternation of Generations Biology Online Tutorial, Sporophytes are produced by the process of meiosis, Gametophytes are produced by the process of mitosis, Sporophyte generation are diploids having 2n chromosomes, Gametophyte generations are haploids having n chromosomes, Sporophytes produce spores having a diploid (2n) number of chromosomes by the, The gametophyte produces gametes having haploid (n) number of chromosomes, Sporophytes are produced by the fusion of the haploid gametes, Gametophytes are produced by the process of spore germination, Microspores (that eventually form male gametophytes), Megaspores (that eventually form female gametophyte). As outlined above, gene losses are predicted to be minor in haploid plants, yet many genes were found on the C. purpureus U and V (more than 3000 transcripts each). Comparisons with the progenitor autosomes gene contents should also yield estimates of the extent of degeneration in the times since recombination was suppressed. Mosses are very sensitive to air pollution and are used to monitor air quality. In a bryophyte, all the conspicuous vegetative organsincluding the photosynthetic leaf-like structures, the thallus (plant body), stem, and the rhizoid that anchors the plant to its substratebelong to the haploid organism or gametophyte. Mosses are often epiphytes. Select the best alternative for the bold word from the given options. It is important to note here that pertaining to the multiplicity of spores in bryophytes, all are bryophytes homosporous. The haploid spores germinate and give rise to the next generation of gametophytes. mature leaves of a given shoot are usually all similar in size and shape. Archegonia are consisting of although they may form large masses in favorable habitats such as moist, shaded rocks or soil, tree trunks or branches and a (2021) Identification of the sex-determining factor in the liverwort Marchantia polymorpha reveals unique evolution of sex chromosomes in a haploid system. In the animal kingdom, invertebrates, such as protozoans, flatworms, jellyfish, etc, also exhibit alternation of generation. Distinguish between the terms in each of the following pairs of terms: spore, seed gametophyte tissue. Bryophytes (nonvascular plants) are a plant group characterized by lacking vascular tissues. seedless, non-vascular plants What are the major groups of bryophytes? However, the high repetitive content and rearranged order of sequences on the U and V suggest that all the added (formerly recombining) regions have stopped recombining and changed from their autosomal states, again resembling the evolutionary history of the Eutherian mammal Y chromosome. Which of the following statements about the moss life cycle is false? https://doi.org/10.1002/bies.201500040, Braasch I, Peterson S, Desvignes T, McCluskey B, Batzel P, Postlethwait J (2015) A new model army: Emerging fish models to study the genomics of vertebrate evo-devo. 2014), consistent with a WGD event before their radiation. The way in which the alternation of generations occurs in plants depends on the type of plant. Water is required for transfer of male gametes to archegonium where zygote is formed after fertilisation. The calyptra, derived from the walls of the archegonium, covers the sporangium. Unexpectedly, however, C. purpureus has only one of each type of sex chromosome. Figure 1. The sporophytes bear sporangia which produce spores. zygote a multicellular embryo is formed, which is nourished by the gametophyte. Crandall-Stotler 1984). General Characteristics of Bryophyta (Liverworts, Hornworts and Mosses), Distinguishing In a bryophyte, all the conspicuous vegetative organsincluding the photosynthetic leaf-like structures, the thallus ("plant body"), stem, and the rhizoid that anchors the plant to its substratebelong to the haploid organism or gametophyte. This is supported by high synonymous site divergence (Ks), exceeding 60%, between paralogous genes in C. purpureus inferred to have been created in the WGD (for synonymous sites, selective constraints should not be strong, and such high divergence indicates a long evolutionary time). Unbiased estimates are not yet available, and species numbers studied are small, but the data (reviewed by Allen (1945) and Renner et al. Size :-Liverworts are the simplest of the living plants, and range in size from minuscule, leafy filaments less Alternatively, perhaps one copy of each was lost; this might be possible, provided that each sex chromosome carries a dominant factor ensuring the respective sex organ development. .and the cycle continues. Figure 2. When the haploid spore germinates in a hospitable environment, it generates a multicellular gametophyte . However, these are not stomata, because they do not actively open and close by the action of guard cells. Select the best alternative for the bold word from the given options. than 0.02 in (0.5 mm) in diameter, to plants exceeding 8 in (20 cm) in size. Typically, a portion of the gametophyte, called the calyptra , protects and covers the developing capsule.The haploid hairy Spores dispersed by a However, if degeneration is minor, as predicted, the U and V should each carry many genes, and dosage relationship imbalances should prevent one copy being lost from such polyploid bryophytes (unless the relative dosage of genes carried on the U and V to autosomal genes is unimportant). Forms by the fusion of the haploid gametes, 5. Alternation of generation is also sometimes referred to as metagenesis or heterogenesis. Andreaea, Drummondia, and Leucodon, germination is reproduction). More than 10,000 species of mosses have been catalogued. Internet Explorer). PubMed Central Perichaetia in pleurocarps are produced at the tips of very short, basally BMC Evol Biol 13:239, Waters PD, Duffy B, Frost CJ, Delbridge ML, Graves JAM (2001) The human Y chromosome derives largely from a single autosomal region added to the sex chromosomes 80-130 million years ago. Thin branched cells called pseudoelaters surround the spores and help propel them farther in the environment. the rest of the land plants, they evolved from green algal ancestors, closely related to the Charophytes. 1. leptoid. In the given sentence a word has been emboldened. Mosses are more complex than liverworts. It is thallus-like and prostrate or erect and attached to the substratum by rhizoids. The above discussion will clarify critical points like, are sporophytes haploid or diploid? Kenrick, P. (2017). Rhizoids:-Mosses are anchored to their substrates by filamentous, often branched, reddish Since the U and V assembly sizes are both similarly large, they presumably each gained both of these two former autosomes, which were probably added to the recombining (pseudo-autosomal region, or PAR) end of an ancestral U or V chromosome, and then recombined onto the other. Photosynthetic, emergent from gametophyte early in development, Hyaline, elongating just prior to spore release, Complex with operculum, theca and neck; of fixed size, Undifferentiated, spherical or elongate; of fixed size. More than 25,000 species of bryophytes thrive in mostly damp habitats, although some live in deserts. The xylem-like Inside adult animal ovaries or testes, diploid (2n) germline cells xxxproduce haploid (n) gametes(ovaor sperm) via meiosis. 2014), suggesting the possibility of independent fusions during the radiation (rather than one event before their radiation). As a result, such plants preferentially grow in a humid environment. 2021), its autosomes may thus carry around 13,100 genes in total; since autosomes 2 and 9 represent 18% of the genome, around 2500 genes might have been added to the U and V (assuming similar gene densities for all autosomes, and no differential re-diploidisation after the WGD). What is Indias primary mode of transport? Spores are produced as a direct result of meiosis. The slender seta (plural, setae), as seen in Figure, contains tubular cells that transfer nutrients from the base of the sporophyte (the foot) to the sporangium or capsule. This agrees fairly well with the numbers inferred in the assembly, so it appears consistent with the prediction of few losses from either the U or the V. Losses are, however, discussed further below. Describe at least one similarity and one difference between bryophyte reproduction and green algae reproduction. :-Acrocarps are characterized by erect or ascending shoot systems that are either unbranched or only sparingly branched. Physical characteristics Description Chloroplasts (green discs) and accumulated starch granules in cells of Bryum capillare Botanically, mosses are non-vascular plants in the land plant division Bryophyta. Syngamy of the egg and sperm produce a zygote within the archegonium. The male gametes in these plants swim through the water to reach the female gamete. The primary function of sporophytes is to produce spores. A final interesting question is whether the sex chromosome of this moss are homologues of those in other bryophytes. If the total gene number in C. purpureus is similar to the estimated 16,545 protein-coding genes in S. caninervis (Silva et al. .. Places to grow. 2007), based on a small number of AFLP markers (which may not imply a physically small size, as repetitive sequences in the UV-linked region could provide disproportionately many such markers per megabase). Cells akin to an apical meristem actively divide and give rise to a gametophore, consisting of a photosynthetic stem and foliage-like structures. substrate with multicellular rhizoids . There are variations in branches that arise from it (C. La Farge 1996). Some mosses have small branches. Liverworts (Hepaticophyta) are currently classified as the plants most closely related to the ancestor of vascular plants that adapted to terrestrial environments. lineages. Branching is typically sympodial with the branches morphologically comparable to the determinant main shoot from which they These plants are further classified as: Figure 5: The life cycle of Angiosperms. Their low gene densities reflect the repeat accumulation expected in non-recombining regions (Charlesworth et al. All 648 single-copy genes were presumably once present on both the U and V, but only 53% are still present on both, while around 85% have now been lost from the U and 68% from the V. These numbers support the prediction that degeneration should affect both haploid sex chromosomes roughly equally, but not that gene losses should be minor. Characteristics of Mosses :-Mosses are mostly-terrestrial bryophytes.Mosses are found in a range of habitats, Therefore, either the fusions with autosomes that created the present UV gene pairs both occurred long after the WGD, or else recombination in both added regions continued for a long time afterwards (but stopped long enough ago for considerable accumulation of repetitive sequences, and for gene orders to become rearranged between the U and V). They lack true stomata, which are present in hornworts and mosses. For sexual reproduction, the The gametophytes bear male and female sex organs called antheridia and archegonia, respectively. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Neil was not very amused by the prank pulled by his sonbecause his car ended up getting damaged. Examples of non-vascular plants are bryophytes and algae. 1(a)), thus bearing a single sporangium at its tip, at maturity.This simple organization is thought to have arisen from a basic sporophyte consisting solely of a sporangium (Mishler and Churchill, 1984), by intercalation of a brief phase of apical meristematic . They are: The extent of dominance of these phases varies between different plant species and algae. hygroscopic) and when wet or very humid weather occurs, they The leafy shoot continues to grow by mitotic division Hornworts have colonized a variety of habitats on land, although they are never far from a source of moisture. Like The sporophyte and gametophyte stages in the algae are similar and hence sometimes referred to as isomorphic. 3. These plants (in either generation) lack specialized cells for the transport of Sci Rep. 9:8722, McDaniel SF, Willis JH, Shaw AJ (2007) A linkage map reveals a complex basis for segregation distortion in an interpopulation cross in the moss Ceratodon purpureus. This is also a characteristic of land plants. Google Scholar, Allen CE (1919) The basis of sex inheritance in Sphaerocarpos. antherozoids enter through the open necks and fuses with egg to form diploid zygote. Based on the vascular system or the material transport system of the plants, they can be further classified into non-vascular and vascular plants. Other Dicranidae species should also be studied. Thin branched cells called pseudoelaters surround the spores and help propel them farther in the environment. 2). Depending on the type of pigment possessed and the type of stored food, algae are classified into three classes, namely Chlorophyceae, Phaeophyceae and Rhodophyceae. Both have much higher repetitive content (around 80%) than the autosomes (slightly below 50%), and consequently lower gene densities. It lacks xylem and phloem.The plant body may have conducting tissue. Liverworts are made up of flat, lobed thalli (singular=thallus, it looks like a liver). J Exp Zool 324:316341. swollen lateral branches that are very short, morphologically distinct from the vegetative branches. Qiu, Y. L., Taylor, A. At this stage, let us understand the difference between Gametophyte and Sporophytes (Table 1). mechanism which ensures dispersal in dry weather only. The spores are single nucleated propagative microscopic structures that have the primary function of spreading the plant culture and reproduction. Mosses have radial symmetry, in that a cut down the long axis of an What are spores in plants? Vascular plants are further subdivided into seedless vascular plants and seed-bearing vascular plants. biflagellated Spores from these sporophytes recapitulate the genotype of their single haploid parent. Several leafy liverworts are shown in Figure. The sporangium is attached to the gametophyte and obtains its nutrition with the help of a small stalk known as seta (Figure 2). A botanist travels to an area that has experienced a long, severe drought. currents, and later they germinate into protonemae. Fragmentation of the gametophyte also results in vegetative reproduction: each living fragment has the potential to grow into a complete gametophyte. UNIVERSAL. Division - Anthocerotophyta(Hornworts). Unique features of the plant life cycle and their consequences. operculum beneath which is a double row of triangular peristome teeth. The moss sporangium is a complex structure that allows release of spores away from the parent plant. This compelling fact is used as evidence that non-vascular plants must have preceded the Silurian period. Addition to both members of a sex chromosome pair might be favoured as it ensures reliable segregation of the ancestrally autosomal element (Blackmon and Demuth 2015). Bibl Genet 3:162, Zimmerman JK (1991) Ecological correlates of labile sex expression in the orchid Catasetum viridiflavum. This initiates the growth of the leafy gametophore Plant Cell 16:S61S71, Vicoso B (2019) Molecular and evolutionary dynamics of animal sex-chromosome turnover. The haploid organism is the dominant part of the life cycle. Which of the following is/are incorrect according to the passage? A liverwort, Lunularia cruciata, displays its lobate, flat thallus. Below are the basic types of spores in plants. However, only 12 autosomes were found (not 14, the expected number after the polyploidisation event). How land plant life cycles first evolved. Figure represents the lifecycle of a lobate liverwort. Correspondence to The authors conclude that the genes that are still found on both the U or V of C. purpureus, are unexpectedly often involved in male or female co-expression modules. Sphagnum also has a dominant gametophyte stage while sphagnum sporophyte is short-lived. anatomically complex, consisting of a differentiated epidermal layer, a cortex, 2003), indicating clearly that the loss of recombination was not a direct consequence of the addition event. Science 286:964967, Marks R, Smith J, Cronk Q, Grassa C, McLetchie D (2019) Genome of the tropical plant Marchantia inflexa: implications for sex chromosome evolution and dehydration tolerance. Selection of the candidates is based on their performance in the prelims exam, mains exam and interview. Why are several aspects of transportation in India still riddled with problems? the developing sporophyte are provided by the gametophyte. The term "sporangia" literally means "spore in a vessel": it is a reproductive sac that contains spores. In the given sentence a word has been emboldened. Mosses exhibit a more complex, multicellular rhizoid system. Bryophyte gametotangia protect the gametes and the growing embryo. A seta or stalk :- which The gametophytes produce gametes having the haploid number of chromosomes (n) by the process of meiosis. Their habitats vary from the tundra, where they are the main vegetation, to the understory of tropical forests. Meiosis in the capsule produces haploid spores. Bryophytes make sporangium to produce spores. The main stems of Sphagnum (Superclass II) display a furcate or dichotomous branch architecture (H. A. Crum 1984). In the majority of mosses, germination is Bryophytes form a monophyletic group that transitions between green algae and vascular plants. The cycle starts with the release of haploid spores from the sporangium that developed on the sporophyte. Many hornworts establish symbiotic relationships with cyanobacteria that fix nitrogen from the environment. A sporangium (capsule) :- Sporogenous tissue forms around the Select the best alternative for the bold word from the given options. There are two kinds of liverworts based on body form: Perichaetia are differentiated at the tip of the main or primary shoot and terminate its growth, so further plant Another bryophyte is Polystichum, which has a dominant gametophyte stage. Am Naturalist 112:245250, Carey SB, Jenkins J, Payton AC, Shu S, Lovell JT, Maumus F et al. Am J Bot 101:15881596, Renner SS, Heinrichs J, Sousa A (2017) The sex chromosomes of bryophytes: Recent insights, open questions, and reinvestigations of Frullania dilatata and Plagiochila asplenioides. This is a characteristic of land plants. In the given sentence a word has been emboldened. At maturity, the tip of Journal of Systematics and Evolution, 50(3), 171-194. When they unite, the resulting cell is diploid and the ensuing embryo continues its development as a diploid individual. The spores germinate to form gametophytes which require cool, damp. Instead, the thallus takes up water over its entire surface and has no cuticle to prevent desiccation, which explains their preferred wet habitats. Haploid spores germinate into flattened thalli attached to the substrate by thin, single-celled filaments. The life cycle of such plants alternates between the haploid (n) gametophyte stage and the diploid (2n) sporophyte stage. divergence between successive derivatives is responsible for the spatial arrangement of the leaves or phyllotaxy of the shoot. Which of the following does not properly describe a sporophyte? branching.In such systems, the indeterminant main stem may be morphologically distinct from the secondary and tertiary level Nature 431:946957, Lahn BT, Page DC (1999) Four evolutionary strata on the human X chromosome. Genetics 176:24892500, Ming R, Bendahmane A, Renner S (2011) Sex chromosomes in land plants. The zygote produces a sporophyte. Which of the following comes closest in meaning to the word liberalization as given in the passage? Without a vascular system and roots, they absorb water and nutrients on all their exposed surfaces. These groups of plants require external water, usually in the form of dew or rain. In the sporophyte phase a diploid (having two sets of chromosomes) plant body grows and eventually . These tutorials will help you learn and appreciate plants regarding their distinctive structures and remarkable inherent strategies for thriving and survival. The sporophyte is attached and dependent upon the gametophyte for nutrition i.e. More studies of other bryophytes that have not undergone WGD events, such as some liverworts (Renner et al. The plants that possess xylem and phloem and produce seeds fall under the category of seed-bearing vascular plants. Charlesworth, D. The mysterious sex chromosomes of haploid plants. gametophyte, or the protonema, which in turn forms the typical gametophyte. Once released, the male gametes swim with the aid of their flagella to an archegonium, and fertilization ensues. A. The embryo grows & forms a mature The gametophyte of some bryophyte species reproduces asexually, or vegetatively, by specialized masses of cells ( gemmae) that are usually budded off and ultimately give rise to gametophytes. If none follows select option 5 as your answer. Mosses exhibit a primitive conductive system in their stalks that transports nutrients and water. ], Leafy shoot or thallus; thallus simple or with air chambers, Present in both gametophytes and sporophytes, Present only in a few simple thalloid forms, Apical clusters (leafy forms) or on upper surface of thallus. Gametophyte refers to the "gamete-making plant." This generation produces the gametes (egg and sperm) by mitosis. J Exp Zool 17:325336, Pannell J (1997) Mixed genetic and environmental sex determination in an androdioecious population of Mercurialis annua. In moss sporophyte plant, spores are produced in a capsular structure known as sporangium. Water is required for transfer of male gametes to archegonium where zygote is formed after fertilisation. Annu Rev Plant Biol 62:485514, Muller HJ (1914) A gene for the fourth chromosome of Drosophila. The sexual phase is the gametophyte. This growth pattern is unique to the hornworts. The man had the audacity to abandonthe cute, little puppy by the side of the road. Image Credit: Gilbert, 2022. subsequent sporophytes have traditionally been divided into two broad morphological groups:-, Acrocarps This type of dual-phase life cycle (gametophyte and sporophyte stages) is known as the haplodiplontic life cycle. But others are larger in diameter and B. By dedicating a majority of their income to savings, followers of the FIRE movement hope to be able to quit their jobs and live solely off small withdrawals from their ______ decades before they reach age 65. Sporangia in Seedless Plants. In many liverworts, spore dispersal is facilitated by elaterslong single cells that suddenly change shape as they dry out and throw adjacent spores out of the spore capsule. growth occurs only if a branch is produced below the perichaetium; such branches are called subfloral innovations. and a central strand of thin-walled, hydrolyzed water conducting cells, called hydroids. The bryophyte embryo also remains attached to the parent plant, which protects and nourishes it. 2021). Views expressed here do not necessarily reflect those of Biology Online, its staff, or its partners. The moss lifecycle follows the pattern of alternation of generations as shown in Figure. Such a process probably created the X-added region of Eutherian mammal sex chromosomes (Skaletsky et al. Bryophytes- Non-vascular plants. Although the term non-tracheophyte is more accurate, bryophytes are commonly called non-vascular plants. The gametophytes bear male and female sex organs called antheridia and archegonia, respectively.