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Embryophyte
Embryophyte
Embryophyte
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Land plants
Temporal range: Mid Ordovician–Present[1][2] (potential Cambrian origin)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Embryophytes
Divisions

Traditional groups:

Synonyms

The embryophytes (/ˈɛmbriəˌfaɪts/) are a clade of plants, known as Embryophyta (Plantae sensu strictissimo) (/ˌɛmbriˈɒfətə, -oʊˈfaɪtə/) or land plants. They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands. Embryophytes have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of freshwater charophyte green algae as a sister taxon of Charophyceae, Coleochaetophyceae and Zygnematophyceae.[10] Embryophytes consist of the bryophytes and the polysporangiophytes.[11] Living embryophytes include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and angiosperms (flowering plants). Embryophytes have diplobiontic life cycles.[12]

The embryophytes are informally called "land plants" because they thrive primarily in terrestrial habitats (despite some members having evolved secondarily to live once again in semiaquatic/aquatic habitats), while the related green algae are primarily aquatic. Embryophytes are complex multicellular eukaryotes with specialized reproductive organs. The name derives from their innovative characteristic of nurturing the young embryo sporophyte during the early stages of its multicellular development within the tissues of the parent gametophyte. With very few exceptions, embryophytes obtain biological energy by photosynthesis, using chlorophyll a and b to harvest the light energy in sunlight for carbon fixation from carbon dioxide and water in order to synthesize carbohydrates while releasing oxygen as a byproduct. The study of land plants is called phytology.

Description

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Moss, clubmoss, ferns and cycads in a greenhouse

The Embryophytes emerged either a half-billion years ago, at some time in the interval between the mid-Cambrian and early Ordovician, or almost a billion years ago, during the Tonian or Cryogenian,[13] probably from freshwater charophytes, a clade of multicellular green algae similar to extant Klebsormidiophyceae.[14][15][16][17] The emergence of the Embryophytes depleted atmospheric CO2 (a greenhouse gas), leading to global cooling, and thereby precipitating glaciations.[18] Embryophytes are primarily adapted for life on land, although some are secondarily aquatic. Accordingly, they are often called land plants or terrestrial plants.[citation needed]

On a microscopic level, the cells of charophytes are broadly similar to those of chlorophyte green algae, but differ in that in cell division the daughter nuclei are separated by a phragmoplast.[19] They are eukaryotic, with a cell wall composed of cellulose and plastids surrounded by two membranes. The latter include chloroplasts, which conduct photosynthesis and store food in the form of starch, and are characteristically pigmented with chlorophylls a and b, generally giving them a bright green color. Embryophyte cells also generally have an enlarged central vacuole enclosed by a vacuolar membrane or tonoplast, which maintains cell turgor and keeps the plant rigid.[citation needed]

In common with all groups of multicellular algae they have a life cycle which involves alternation of generations. A multicellular haploid generation with a single set of chromosomes – the gametophyte – produces sperm and eggs which fuse and grow into a diploid multicellular generation with twice the number of chromosomes – the sporophyte which produces haploid spores at maturity. The spores divide repeatedly by mitosis and grow into a gametophyte, thus completing the cycle. Embryophytes have two features related to their reproductive cycles which distinguish them from all other plant lineages. Firstly, their gametophytes produce sperm and eggs in multicellular structures (called 'antheridia' and 'archegonia'), and fertilization of the ovum takes place within the archegonium rather than in the external environment. Secondly, the initial stage of development of the fertilized egg (the zygote) into a diploid multicellular sporophyte, takes place within the archegonium where it is both protected and provided with nutrition. This second feature is the origin of the term 'embryophyte' – the fertilized egg develops into a protected embryo, rather than dispersing as a single cell.[15] In the bryophytes the sporophyte remains dependent on the gametophyte, while in all other embryophytes the sporophyte generation is dominant and capable of independent existence.[citation needed]

Embryophytes also differ from algae by having metamers. Metamers are repeated units of development, in which each unit derives from a single cell, but the resulting product tissue or part is largely the same for each cell. The whole organism is thus constructed from similar, repeating parts or metamers. Accordingly, these plants are sometimes termed 'metaphytes' and classified as the group Metaphyta[20] (but Haeckel's definition of Metaphyta places some algae in this group[21]). In all land plants a disc-like structure called a phragmoplast forms where the cell will divide, a trait only found in the land plants in the streptophyte lineage, some species within their relatives Coleochaetales, Charales and Zygnematales, as well as within subaerial species of the algae order Trentepohliales, and appears to be essential in the adaptation towards a terrestrial life style.[22][23][24][25]

Evolution

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The green algae and land plants form a clade, the Viridiplantae. According to molecular clock estimates, the Viridiplantae split 1,200 million years ago to 725 million years ago into two clades: chlorophytes and streptophytes. The chlorophytes, with around 700 genera, were originally marine algae, although some groups have since spread into fresh water. The streptophyte algae (i.e. excluding the land plants) have around 122 genera; they adapted to fresh water very early in their evolutionary history and have not spread back into marine environments.[26][27][28]

Some time during the Ordovician, streptophytes invaded the land and began the evolution of the embryophyte land plants.[29] Present day embryophytes form a clade.[30] Becker and Marin speculate that land plants evolved from streptophytes because living in fresh water pools pre-adapted them to tolerate a range of environmental conditions found on land, such as exposure to rain, tolerance of temperature variation, high levels of ultra-violet light, and seasonal dehydration.[31]

The preponderance of molecular evidence as of 2006 suggested that the groups making up the embryophytes are related as shown in the cladogram below (based on Qiu et al. 2006 with additional names from Crane et al. 2004).[32][33]

Living embryophytes

An updated phylogeny of Embryophytes based on the work by Novíkov & Barabaš-Krasni 2015[34] and Hao and Xue 2013[35] with plant taxon authors from Anderson, Anderson & Cleal 2007[36] and some additional clade names.[37] Puttick et al./Nishiyama et al. are used for the basal clades.[11][38][39]

Embryophytes
Paratracheophytes
Lycophytes

Diversity

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Non-vascular land plants

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Further information: Alternation of generations
Bryophytes, such as these mosses, produce unbranched, stalked sporophytes from which their spores are released.

The non-vascular land plants, namely the mosses (Bryophyta), hornworts (Anthocerotophyta), and liverworts (Marchantiophyta), are relatively small plants, often confined to environments that are humid or at least seasonally moist. They are limited by their reliance on water needed to disperse their gametes; a few are truly aquatic. Most are tropical, but there are many arctic species. They may locally dominate the ground cover in tundra and Arctic–alpine habitats or the epiphyte flora in rain forest habitats.

They are usually studied together because of their many similarities. All three groups share a haploid-dominant (gametophyte) life cycle and unbranched sporophytes (the plant's diploid generation). These traits appear to be common to all early diverging lineages of non-vascular plants on the land. Their life-cycle is strongly dominated by the haploid gametophyte generation. The sporophyte remains small and dependent on the parent gametophyte for its entire brief life. All other living groups of land plants have a life cycle dominated by the diploid sporophyte generation. It is in the diploid sporophyte that vascular tissue develops. In some ways, the term "non-vascular" is a misnomer. Some mosses and liverworts do produce a special type of vascular tissue composed of complex water-conducting cells.[40] However, this tissue differs from that of "vascular" plants in that these water-conducting cells are not lignified.[41] It is unlikely that the water-conducting cells in mosses are homologous with the vascular tissue in "vascular" plants.[40]

Like the vascular plants, they have differentiated stems, and although these are most often no more than a few centimeters tall, they provide mechanical support. Most have leaves, although these typically are one cell thick and lack veins. They lack true roots or any deep anchoring structures. Some species grow a filamentous network of horizontal stems, but these have a primary function of mechanical attachment rather than extraction of soil nutrients (Palaeos 2008).

Rise of vascular plants

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Reconstruction of a plant of Rhynia

During the Silurian and Devonian periods (around 440 to 360 million years ago), plants evolved which possessed true vascular tissue, including cells with walls strengthened by lignin (tracheids). Some extinct early plants appear to be between the grade of organization of bryophytes and that of true vascular plants (eutracheophytes). Genera such as Horneophyton have water-conducting tissue more like that of mosses, but a different life-cycle in which the sporophyte is branched and more developed than the gametophyte. Genera such as Rhynia have a similar life-cycle but have simple tracheids and so are a kind of vascular plant.[42] It was assumed that the gametophyte dominant phase seen in bryophytes used to be the ancestral condition in terrestrial plants, and that the sporophyte dominant stage in vascular plants was a derived trait. However, the gametophyte and sporophyte stages were probably equally independent from each other, and that the mosses and vascular plants in that case are both derived, and have evolved in opposite directions.[43]

During the Devonian period, vascular plants diversified and spread to many different land environments. In addition to vascular tissues which transport water throughout the body, tracheophytes have an outer layer or cuticle that resists drying out. The sporophyte is the dominant generation, and in modern species develops leaves, stems and roots, while the gametophyte remains very small.

Further information: Polysporangiophyte, Horneophytopsida, and Rhyniopsida

Lycophytes and euphyllophytes

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Lycopodiella inundata, a lycophyte
Main article: Lycopodiophyta

All the vascular plants which disperse through spores were once thought to be related (and were often grouped as 'ferns and allies'). However, recent research suggests that leaves evolved quite separately in two different lineages. The lycophytes or lycopodiophytes – modern clubmosses, spikemosses and quillworts – make up less than 1% of living vascular plants. They have small leaves, often called 'microphylls' or 'lycophylls', which are borne all along the stems in the clubmosses and spikemosses, and which effectively grow from the base, via an intercalary meristem.[44] It is believed that microphylls evolved from outgrowths on stems, such as spines, which later acquired veins (vascular traces).[45]

Although the living lycophytes are all relatively small and inconspicuous plants, more common in the moist tropics than in temperate regions, during the Carboniferous period tree-like lycophytes (such as Lepidodendron) formed huge forests that dominated the landscape.[46]

The euphyllophytes, making up more than 99% of living vascular plant species, have large 'true' leaves (megaphylls), which effectively grow from the sides or the apex, via marginal or apical meristems.[44] One theory is that megaphylls evolved from three-dimensional branching systems by first 'planation' – flattening to produce a two dimensional branched structure – and then 'webbing' – tissue growing out between the flattened branches.[47] Others have questioned whether megaphylls evolved in the same way in different groups.[48]

Ferns and horsetails

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Main article: Fern

The ferns and horsetails (the Polypodiophyta) form a clade; they use spores as their main method of dispersal. Traditionally, whisk ferns and horsetails were historically treated as distinct from 'true' ferns.[49] Living whisk ferns and horsetails do not have the large leaves (megaphylls) which would be expected of euphyllophytes. This has probably resulted from reduction, as evidenced by early fossil horsetails, in which the leaves are broad with branching veins.[50]

Ferns are a large and diverse group, with some 12,000 species.[51] A stereotypical fern has broad, much divided leaves, which grow by unrolling.

Seed plants

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Main article: Spermatophyte
Large seed of horse chestnut, Aesculus hippocastanum

Seed plants, which first appeared in the fossil record towards the end of the Paleozoic era, reproduce using desiccation-resistant capsules called seeds. Starting from a plant which disperses by spores, highly complex changes are needed to produce seeds. The sporophyte has two kinds of spore-forming organs or sporangia. One kind, the megasporangium, produces only a single large spore, a megaspore. This sporangium is surrounded by sheathing layers or integuments which form the seed coat. Within the seed coat, the megaspore develops into a tiny gametophyte, which in turn produces one or more egg cells. Before fertilization, the sporangium and its contents plus its coat is called an ovule; after fertilization a seed. In parallel to these developments, the other kind of sporangium, the microsporangium, produces microspores. A tiny gametophyte develops inside the wall of a microspore, producing a pollen grain. Pollen grains can be physically transferred between plants by the wind or animals, most commonly insects. Pollen grains can also transfer to an ovule of the same plant, either with the same flower or between two flowers of the same plant (self-fertilization). When a pollen grain reaches an ovule, it enters via a microscopic gap in the coat, the micropyle. The tiny gametophyte inside the pollen grain then produces sperm cells which move to the egg cell and fertilize it.[52] Seed plants include two clades with living members, the gymnosperms and the angiosperms or flowering plants. In gymnosperms, the ovules or seeds are not further enclosed. In angiosperms, they are enclosed within the carpel. Angiosperms typically also have other, secondary structures, such as petals, which together form a flower.

Meiosis in sexual land plants provides a direct mechanism for repairing DNA in reproductive tissues.[53] Sexual reproduction appears to be needed for maintaining long-term genomic integrity and only infrequent combinations of extrinsic and intrinsic factors allow for shifts to asexuality.[53]

References

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Bibliography

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Embryophyte

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Embryophytes, commonly referred to as land plants, are a monophyletic clade of multicellular, eukaryotic organisms within the kingdom Plantae that are primarily terrestrial and autotrophic, distinguished by their ability to retain and nourish a multicellular diploid embryo within protective maternal tissues during reproduction. This defining embryogenic trait, along with adaptations such as a waxy cuticle to prevent desiccation, stomata for gas exchange, and spores walled with sporopollenin for protection, enabled their transition from aquatic ancestors to dominating terrestrial ecosystems. Key characteristics of embryophytes include a haplo-diplontic life cycle featuring between a haploid phase and a diploid phase, with primary chloroplasts derived from endosymbiotic . In non-vascular embryophytes (bryophytes), the is dominant and photosynthetic, while the is dependent; in contrast, vascular embryophytes exhibit a dominant with specialized conducting tissues ( and ) containing lignin-reinforced tracheids. These innovations, including archegonia and antheridia for and sporangia for dispersal, underscore their to life on land. Embryophytes are classified into four major lineages: Marchantiophyta (liverworts, ~7,000–8,500 ), Bryophyta (mosses, ~12,000–13,000 ), Anthocerophyta (hornworts, ~200–300 ), and Tracheophyta (vascular plants, >320,000 , encompassing lycophytes, ferns, gymnosperms, and angiosperms) (as of 2024). The tracheophytes further divide into lycophytes (e.g., clubmosses) and euphyllophytes (ferns and seed plants), with angiosperms (flowering plants) representing the most diverse group at ~300,000–370,000 and dominating modern vegetation. Overall, embryophytes encompass approximately 390,000 described , forming the backbone of terrestrial (as of 2024). Evolutionarily, embryophytes originated from streptophyte green algae, specifically Zygnematophyceae (such as Zygnematales), during the Middle Ordovician period around 470 million years ago (molecular clock estimates as of 2020s), with the earliest potential fossil evidence as cryptospores from the Mid-Ordovician (~470 Ma), and definitive trilete spores appearing in the Early Silurian (~430 Ma). Their radiation involved sequential innovations like vascular tissues in the Silurian-Devonian and seeds in the late Devonian, leading to the colonization of diverse habitats from arctic tundras to tropical rainforests.

Definition and Characteristics

Definition

Embryophytes, also known as land plants or the Metaphyta, constitute a monophyletic group within the green plants () that encompasses all terrestrial plants, including the non-vascular bryophytes—such as hornworts, liverworts, and mosses—and the vascular tracheophytes, which comprise ferns, lycophytes, gymnosperms, and angiosperms. This is distinguished from aquatic by its to terrestrial environments, though some embryophytes have secondarily returned to aquatic habitats. The defining characteristic of embryophytes is the development of a multicellular diploid that arises from the and is nourished and protected within the of the female by parental tissues, marking a key innovation in the diplohaplontic life cycle. This embryogenic phase, absent in their algal ancestors, ensures the survival of the young in desiccating conditions. The of embryophytes is robustly supported by shared derived traits (synapomorphies), including a multilayered of waxy that minimizes water loss from aerial surfaces; and, in most lineages, stomata—specialized pores that regulate while conserving moisture. These innovations arose following the divergence of embryophytes from their closest algal relatives, the charophyte (Streptophyta), during the period.

Life Cycle and Reproduction

Embryophytes exhibit a diplobiontic life cycle characterized by , featuring a multicellular haploid phase that produces gametes and a multicellular diploid phase that produces . This haplodiplontic cycle represents an autapomorphy of embryophytes, distinguishing them from their charophycean algal ancestors, where generations were often isomorphic or one phase dominated without a dependent . In this cycle, the develops from a haploid and nourishes the developing sporophyte , which arises from fertilization within the female gametangium. The is the dominant, photosynthetic phase in early-diverging embryophytes like bryophytes, where it is free-living and produces gametes through in specialized structures: antheridia for biflagellated and archegonia for . Fertilization requires a film of for to swim to the , after which the develops into an retained and nourished (matrotrophy) by the parental via nutrient transfer, such as sugars. In contrast, the emerges as the larger, dependent phase in these groups but becomes the independent, dominant generation in vascular embryophytes, with the reduced in size. Spores are produced by within sporangia on the , typically forming tetrads that are dispersed to initiate new gametophytes. In lineages, such as liverworts and hornworts, spore dispersal is aided by sterile cells called elaters (in liverworts) or pseudo-elaters (in hornworts), which are hygroscopic and twist or expand with moisture changes to liberate . This mechanism enhances wind dispersal in terrestrial environments. Across embryophytes, the alternation is heteromorphic, with differing morphologies and sizes between generations, unlike the isomorphic alternation in some algal ancestors where phases were similar. In vascular embryophytes, the sporophyte's dominance reflects evolutionary elaboration, while the remains essential for reproduction but is often internalized or reduced.

Structural Adaptations to Land

Embryophytes, as terrestrial , exhibit a waxy that forms an extracellular hydrophobic layer covering the aerial , primarily composed of cutin polymers and overlaid waxes, which serves as a primary barrier against by minimizing uncontrolled loss from surfaces. This is universal across embryophytes, enabling survival in air where rates are high compared to aquatic environments. The 's composition, including long-chain fatty acids and polyesters, provides mechanical strength and impermeability to and solutes, as detailed in studies on its and deposition. In most embryophytes, the is perforated by stomata—specialized pores flanked by —that facilitate for and respiration while permitting regulated to prevent excessive loss; these are absent in liverworts but present on sporophytes in mosses and hornworts, and on vegetative structures in vascular embryophytes (tracheophytes). Stomatal density and aperture are dynamically controlled by environmental cues like , CO₂ levels, and , balancing CO₂ uptake with , a critical for . While liverworts rely on a continuous without stomata, the regulated stomatal system in mosses, hornworts, and tracheophytes supports larger body sizes and efficient resource acquisition in variable terrestrial conditions. Tracheophytes possess vascular tissues absent in bryophytes: xylem, consisting of lignified, dead tracheids and vessels for unidirectional water and mineral conduction driven by transpiration pull, and , with living elements and companion cells for bidirectional of photosynthates like sugars. These tissues enable efficient long-distance distribution, supporting upright growth and larger statures on land. Bryophytes, lacking vascular systems, rely on for short-distance , limiting their size and habitat to moist environments./25%3A_Seedless_Plants/25.04%3A_Seedless_Vascular_Plants/25.4B%3A_Vascular_Tissue-_Xylem_and_Phloem) For anchorage and nutrient uptake, bryophytes employ rhizoids—simple, filamentous extensions of epidermal cells that primarily anchor the plant body to substrates and absorb water and minerals via over short distances, without vascular connections or true absorptive tips. In contrast, vascular develop true with apical meristems, vascular cylinders, and root hairs, providing robust anchorage, extensive soil penetration, and efficient absorption through specialized endodermal barriers, facilitating to drier . Photosynthetic adaptations in embryophytes include chlorophyll a as the primary pigment for light harvesting in photosystem reaction centers, supplemented by chlorophyll b and accessory pigments like carotenoids and xanthophylls, which expand the absorption spectrum to include blue and red wavelengths while protecting against excess light via dissipation. These pigments enable efficient energy capture under terrestrial light regimes. Additionally, while the basal C3 pathway fixes CO₂ via Rubisco in mesophyll cells, C4 and CAM variants—found in certain angiosperms and succulents—concentrate CO₂ spatially (C4) or temporally (CAM) to minimize photorespiration in hot, arid, or low-light conditions, enhancing water-use efficiency.

Evolutionary History

Origins and Early Divergence

Embryophytes, or land , originated within the clade of , sharing a common ancestry with streptophyte algae, with the Zygnematophyceae (conjugating ) identified as their closest algal relatives. The broader lineage diverged from the (core ) approximately 725–1,200 million years ago during the era, a split potentially influenced by extreme climatic events like the glaciations, or "" periods. This ancient divergence established foundational streptophyte characteristics, including the phragmoplast-mediated , which facilitated in multicellular structures and pre-adapted ancestors for terrestrial complexity. Molecular clock analyses estimate the specific divergence of embryophytes from their closest algal relatives around 500 million years ago in the period, marking the initial formation of the embryophyte . The earliest evidence supporting this transition consists of cryptospore assemblages—tetrads of resistant spores indicative of embryophyte-like —dated to 470–450 million years ago in the Early to Middle . These spores, found in sedimentary rocks from sites like and , exhibit morphologies intermediate between algal zygospores and definitive land plant spores, suggesting a gradual shift from aquatic to subaerial habitats where embryonic development within protective tissues became advantageous. A pivotal innovation in embryophyte formation involved bursts of genomic novelty, including duplications and potential whole-genome duplication events, which expanded genetic repertoire for terrestrial adaptations such as signaling and stress responses. These genomic changes, occurring around the embryophyte last common ancestor, enabled the evolution of traits like cuticular waxes for resistance and UV-protective compounds. Environmental pressures during the , including low atmospheric oxygen (O₂) levels below 15% present atmospheric levels and fluctuating (CO₂) concentrations around 400–700 ppm, alongside elevated (UV) exposure due to a thin , strongly selected for these protective features in early embryophytes. The combination of hypoxic conditions and intense UV radiation likely favored the retention of algal-derived mechanisms for oxygen acquisition and , driving the selective advantage of land colonization.

Major Evolutionary Transitions

One of the pivotal innovations in embryophyte evolution was the shift from gametophyte-dominant life cycles, as seen in bryophytes, to sporophyte-dominant cycles in vascular plants. This transition involved changes in genetic regulation that promoted the development and indeterminacy of the sporophyte phase. Genes such as KNOX and BELL family transcription factors, which control maintenance and branching, played key roles in decoupling proliferative growth from reproduction, allowing the sporophyte to become the dominant, independent generation. In bryophytes like mosses, the gametophyte remains the primary photosynthetic phase, while in vascular plants, the develops complex structures such as stems and leaves, reflecting small genetic modifications that drove this morphological shift. Vascularization marked another critical transition, enabling embryophytes to achieve upright growth and greater stature through the evolution of specialized conducting tissues. Tracheids in the , characterized by lignified secondary walls with pits, provided mechanical support and efficient water transport against gravity, while sieve elements in the facilitated the distribution of sugars and nutrients. These tissues first appeared during the period around 440 million years ago, originating from primitive conducting strands in early land and allowing for the evolution of taller, more complex forms beyond the prostrate habits of non-vascular bryophytes. The lignification of tracheids was particularly transformative, conferring hydrophobicity and rigidity essential for terrestrial adaptation. The development of represented a major reproductive , transitioning embryophytes from reliance on spores to enclosed, protective structures that enhanced survival in arid environments. This shift occurred in the late around 370 million years ago, evolving from progymnosperm ancestors through the enclosure of megasporangia by integuments, which formed protective layers around the . incorporated features like mechanisms and chambers, providing resistance to and enabling delayed , unlike the moisture-dependent dispersal of spores in earlier plants. Integuments, initially dissected into segments, improved efficiency and nourishment, laying the foundation for diversification. Megaphyll evolution in euphyllophytes introduced leaf-like structures optimized for photosynthesis, contrasting with the simpler microphylls of lycophytes. According to Zimmermann's telome theory, megaphylls arose from three-dimensional, dichotomously branching axes (telomes) of early vascular plants through a series of transformations: overtopping, where one branch elongates dominantly to form a main axis; planation, flattening the branches into a single plane; and webbing, or syngenesis, filling gaps with laminar tissue to create a blade. These processes, which could occur in varying sequences, resulted in complex, veined leaves that maximized light capture, differing from lycophyte microphylls that evolved via enations without such extensive vascular reorganization. This innovation supported the ecological dominance of euphyllophytes like ferns and seed plants.

Timeline and Fossil Evidence

The fossil record of embryophytes begins in the period, with the earliest evidence consisting of cryptospores—fused tetrads indicative of bryophyte-like land s—dating back to approximately 470 million years ago (Ma). These microfossils, found in sedimentary rocks from regions such as and , suggest the initial colonization of land by non-vascular embryophytes, characterized by simple, -producing organisms adapted to terrestrial environments. By the period (around 430 Ma), the first vascular embryophytes appear in the form of , a simple, leafless with dichotomously branching stems and terminal sporangia, preserved in deposits from and other Gondwanan sites. represents a pivotal transition to , enabling greater structural support and water transport on land. The period (420–360 Ma) marks a dramatic diversification of vascular embryophytes, often termed the "Devonian explosion," with fossils revealing complex interactions between gametophyte and sporophyte generations. Exceptional preservation in the of , dating to about 410 Ma, provides detailed insights into early land such as Aglaophyton and Horneophyton, which exhibit independent gametophytes and sporophytes, some with rudimentary vascular tissues and symbiotic fungi. This period saw the emergence of lycophytes, early ferns, and progymnosperms, expanding embryophyte presence into more varied habitats. During the and Permian periods (360–250 Ma), embryophytes dominated terrestrial ecosystems, forming vast swamp forests primarily composed of arborescent lycophytes like and tree ferns such as Psaronius. These wetlands, preserved in measures across Euramerica, supported immense accumulation, contributing to global and atmospheric oxygen levels. Toward the late Permian, gymnosperms began to rise, with seed-producing plants like glossopterids and early appearing in the fossil record, adapting to drier conditions and foreshadowing the decline of lycophyte-dominated forests. The and eras (250 Ma to present) witnessed the radiation of seed plants, particularly angiosperms, which first appear in the fossil record around 140 Ma in the . This diversification, evidenced by pollen and floral fossils from sites like the Dakota Formation, coincided with co-evolution alongside insect pollinators, enabling rapid ecological expansion and the displacement of many gymnosperms.

Phylogenetic Classification

Overall Phylogeny

Embryophytes, or land plants, form a monophyletic clade within the streptophytes, supported by extensive phylogenomic analyses utilizing hundreds of nuclear genes that resolve a shared ancestry distinct from algal relatives. This monophyly is evidenced by the presence of over 100 conserved genes involved in key developmental pathways, such as those governing embryo formation and multicellular sporophyte development, which are absent or divergent in non-embryophyte streptophytes. For instance, orthologs of core genes like those in the SPCH/MUTE, SMF, and FAMA families, essential for stomatal and embryonic patterning, trace back to the last common ancestor of all embryophytes, reinforcing genetic synapomorphies alongside morphological traits like the protected embryo. The overall topology of embryophyte phylogeny reveals bryophytes as a basal grade, with the three lineages—liverworts, mosses, and hornworts—exhibiting in some analyses, though recent studies increasingly support their as sister to vascular (tracheophytes). A prominent hypothesis, Setaphyta, posits mosses and liverworts as a sister to a hornwort-vascular lineage, rendering traditional bryophytes and aligning with mitochondrial and data under heterogeneous substitution models. This contrasts with older models favoring sequential sister relationships among bryophyte groups to vascular , but both frameworks place polysporangiophytes (the branched sporophyte-bearing encompassing tracheophytes) as the derived branch, where lycophytes diverge basally from euphyllophytes (ferns and seed ). Post-2020 advances, driven by whole-genome sequencing of diverse s, have significantly refined deep-node resolutions through integration of transcriptomic and genomic datasets. For example, the sequencing of over 120 bryophyte genomes, including multiple species in 2023 and expanded sets by 2025, has enabled analyses that confirm bryophyte while highlighting expansions unique to land plants, such as de novo origins and horizontal transfers aiding terrestrial adaptation. A 2025 super- analysis of 138 bryophyte genomes (123 newly sequenced) confirms bryophytes as monophyletic sisters to tracheophytes, with Setaphyta (liverworts + es) sister to hornworts. These datasets, combined with phylogenomic trees from thousands of loci, have bolstered support for bryophytes as monophyletic sisters to tracheophytes, with precise divergence estimates around 500 million years ago, and clarified branching within polysporangiophytes by resolving lycophyte-euphyllophyte splits with high bootstrap values.

Non-vascular Clades

The non-vascular clades of embryophytes, collectively known as bryophytes, comprise three monophyletic lineages: Marchantiophyta (liverworts), Anthocerotophyta (hornworts), and Bryophyta (mosses). These groups form a grade at the base of the embryophyte phylogeny, sister to the vascular (tracheophytes), with recent phylogenomic analyses supporting bryophyte monophyly. Internal relationships among bryophytes show liverworts as the earliest diverging, followed by a of mosses and hornworts in some studies, though a 2021 analysis supports bryophyte monophyly, placing hornworts as to the Setaphyta (mosses + liverworts). Bryophytes lack true , relying instead on for water and nutrient transport, and are poikilohydric, tolerating while thriving in moist environments where they often dominate ground cover and contribute to . Marchantiophyta, or liverworts, encompass approximately 6,000 species characterized by that are either thalloid (flat, ribbon-like bodies) or leafy (with small, overlapping leaf-like structures arranged in two or three rows). Thalloid forms, such as those in , feature a dorsiventral with air chambers for , while leafy forms dominate in the Jungermanniales order. A key reproductive adaptation is asexual propagation via gemmae—small, multicellular propagules produced in cup-like structures (gemma cups) on the gametophyte surface, allowing dispersal without spores. Liverworts exhibit a dominant phase, with short-lived, unbranched sporophytes that dehisce longitudinally to release spores. Anthocerotophyta, the hornworts, include around 100–200 species, distinguished by their simple, rosette-forming thalloid and elongated, horn-like that grow continuously from a basal . The , which remains attached and photosynthetically active, features a central for structural support and stomata for gas regulation, traits shared with vascular plants. Hornworts uniquely host symbiotic nitrogen-fixing (e.g., ) in mucilage-filled cavities within the gametophyte , enhancing nutrient acquisition in nutrient-poor soils. Spore dispersal occurs via pseudo-elaters, twisted bands that aid in dehiscence under dry conditions. Bryophyta, or mosses, represent the most species-rich bryophyte group with about 12,000–13,000 species, featuring upright or prostrate leafy s with spirally arranged leaves and anchoring rhizoids—multicellular filaments that lack absorptive function but provide attachment. The leaves are typically one cell thick, with a midrib in many for support, and the often forms dense cushions or turfs. sporophytes are elevated on a and capped by a capsule with a —a ring of hygroscopic teeth that regulates release by responding to changes, optimizing dispersal in variable conditions. Across these clades, bryophytes share a haploid-dominant life cycle with , where the is the prominent, photosynthetic phase, and the diploid is dependent and reduced. Their poikilohydric enables survival in fluctuating moisture levels, but limits size and distribution to humid microhabitats like floors, wetlands, and rock surfaces, where they form extensive mats and play key roles in water retention and .

Vascular and Seed Plant Clades

The vascular plants, or tracheophytes, represent a major monophyletic clade within embryophytes known as Polysporangiophyta, characterized by sporophytes bearing multiple sporangia and complex branching patterns that enabled efficient spore dispersal and structural support on land. This group excludes the non-vascular bryophytes and encompasses all extant seedless vascular plants as well as seed plants, with key innovations including vascular tissues (tracheids and sieve elements) for water and nutrient transport. The Polysporangiophyta diverged early in land plant evolution, around 420 million years ago, and today dominate terrestrial ecosystems through diverse lineages adapted to varied habitats. The Lycopodiophyta, or lycophytes, form one of the basal vascular clades, distinguished by microphylls—small, simple leaves with a single unbranched vein derived from a vascular strand. This group includes approximately 1,300 species across three families: Lycopodiaceae (clubmosses), Selaginellaceae (spikemosses), and Isoëtaceae (quillworts), many of which are heterosporous with separate spores. During the period (about 359–299 million years ago), lycophytes such as the tree-like dominated swamp forests, reaching heights over 35 meters and contributing significantly to deposits through their extensive biomass. Extant species are mostly small, herbaceous thriving in shaded, moist environments, reflecting a reduction in stature since their ancient prominence. Sister to the lycophytes within Polysporangiophyta are the euphyllophytes, which include the Monilophyta and seed plants; the Monilophyta, comprising , horsetails, and relatives, feature megaphylls—larger, complex leaves with branched venation arising from leaf gaps in the vascular . This encompasses around 12,000 , predominantly in the fern order , with additional diversity in (horsetails, about 15 ), Ophioglossales (adder's-tongue ferns, around 100 ), and Marattiales (giant ferns, about 70 ). Reproduction occurs via spores clustered in sori—protective structures on the undersides of fronds—facilitating homosporous or heterosporous life cycles that require water for fertilization. Whisk ferns (Psilotales, including genera and Tmesipteris) represent a basal lineage within Monilophyta, lacking true and leaves in their simple, dichotomously branching sporophytes, highlighting the clade's evolutionary progression toward more elaborate fronds in derived . Seed plants (Spermatophyta) evolved within euphyllophytes as a monophyletic group producing seeds rather than spores, further dividing into gymnosperms and angiosperms. The Acrogymnospermae, or gymnosperms, bear naked seeds exposed on modified leaves or cones, without enclosure in an ovary, and include four extant orders: Cycadales (cycads, about 330 species of palm-like plants with fern-like fronds), (, a single species with fan-shaped leaves), (, over 600 species of trees and shrubs like pines and spruces), and Gnetales (gnetophytes, around 70 species in diverse forms such as Ephedra shrubs and Welwitschia desert perennials). With roughly 1,000 species total, gymnosperms are woody perennials adapted to temperate and boreal regions, playing key roles in forest ecosystems through production and wind-pollinated . The angiosperms (flowering plants) represent the most species-rich of seed plants, with ovules and enclosed within a carpel-derived that develops into , enhancing protection and dispersal. Comprising approximately 300,000 species, angiosperms exhibit extraordinary floral diversity, from simple wind-pollinated grasses to elaborate insect-attracting blooms in orchids and magnolias, driven by with pollinators. Their rapid radiation began in the (around 130 million years ago), accelerating post-Cretaceous boundary with the diversification of and monocots, leading to dominance in most terrestrial biomes through efficient and versatile growth forms.

Diversity and Distribution

Bryophytes

Bryophytes, the non-vascular embryophytes, comprise approximately 20,000 globally, with mosses (Bryophyta) representing about 60% of this diversity (approximately 12,000 ), followed by liverworts (Marchantiophyta; about 8,000 ) and hornworts (Anthocerotophyta; about 200 ). This group exhibits its highest in tropical regions, particularly in moist montane forests where microhabitats support dense assemblages. However, bryophytes play crucial ecological roles in polar and arid zones, where their desiccation tolerance enables survival in extreme environments with limited water availability. These plants occupy diverse habitats, including as epiphytes on tree bark and rocks, colonizers of bare soil, and occupants of aquatic margins in wetlands and streams. A notable example is the genus Sphagnum, which dominates peat-forming bogs and contributes to global carbon storage by accumulating organic matter; these bogs, covering just 3% of Earth's land surface, sequester about 30% of the world's soil carbon. Bryophytes' adaptations include reliance on external water for fertilization, ensuring sperm reach eggs via splashing rain or dew, though many species exhibit resurrection physiology, reviving metabolic activity after prolonged desiccation through protective mechanisms like sugar accumulation and protein stabilization. Distribution patterns of bryophytes are cosmopolitan, with species found on every continent, including , reflecting their broad physiological tolerance. is particularly pronounced in isolated island systems, such as , where unique climatic gradients foster specialized taxa comprising about 7% of the bryophyte flora. Bryophytes are sensitive to habitat fragmentation, which disrupts moisture retention and stability, leading to declines in population connectivity and in fragmented landscapes. As the basal lineages in embryophyte phylogeny, bryophytes highlight early land plant adaptations without vascular tissues.

Vascular Cryptogams

Vascular cryptogams, encompassing seedless vascular such as ferns, horsetails, and lycophytes, total approximately 12,000 globally (as of ), representing a significant portion of non-seed plant diversity. Ferns (Polypodiophyta) dominate with over 10,500 , often thriving in shaded layers of forests where their fronds capture filtered light efficiently. In contrast, lycophytes (Lycopodiophyta), with around 1,200 , frequently occupy and boggy terrains, contributing to ground cover in moist, low-light conditions. Horsetails (Equisetophyta) add a modest ~15 , mostly in damp, open areas. These plants exhibit broad preferences, with the majority of fern species concentrated in tropical rainforests, where they account for up to 80% of the group's diversity in humid, shaded microhabitats. Temperate forests host fewer but notable assemblages, particularly in understories and along stream banks, while aquatic forms like the floating fern (Salviniales) dominate still waters and wetlands. Many species exploit altitudinal gradients, transitioning from lowland rainforests to montane cloud forests, adapting to varying moisture and temperature regimes across elevations from to over 4,000 meters. Key adaptations enhance their survival in these niches. Ferns feature circinate vernation, in which immature fronds coil into protective "fiddleheads" that unfurl as they mature, shielding delicate tissues from desiccation and herbivores. Among lycophytes, occurs in genera like Selaginella, where plants produce small microspores for male gametophytes and larger megaspores for female ones, facilitating efficient reproduction in variable moisture levels. Globally, vascular cryptogams display a distribution, with peak diversity in the humid tropics of , , and ; relictual temperate groups, such as certain clubmosses (), persist in northern hemisphere forests as evolutionary holdovers. Some species, including the widespread bracken fern (), exhibit invasive tendencies in disturbed areas like roadsides and abandoned fields, rapidly colonizing open soils due to their resilient rhizomes and dispersal.

Seed Plants

Seed plants, comprising gymnosperms and angiosperms, represent the most diverse group of embryophytes, with an estimated 370,000 extant (as of 2024), of which approximately 99% are angiosperms (~369,000 ) and the remainder gymnosperms (~1,000 ). Gymnosperms include around 1,000 across four major lineages, with dominating boreal and temperate zones through their adaptation to cold, dry conditions, while angiosperms exhibit extraordinary diversification across virtually all biomes, from tropical rainforests to tundras. This disparity underscores the evolutionary success of angiosperms in exploiting varied ecological niches, far surpassing the more specialized distribution of gymnosperms. Key adaptations in seed plants enable their reproductive independence from , unlike the spore-based systems of vascular cryptogams. occurs via , with gymnosperms primarily relying on and exposed "naked" in cones, whereas angiosperms have evolved flowers that facilitate by , , birds, and other animals, enhancing efficiency and specificity. , driven by the , allows many seed plants to develop woody tissues, supporting tall stature and longevity; this is prominent in coniferous forests and angiosperm-dominated woodlands, contributing to structural complexity in ecosystems. Seed plants occupy an extensive range of habitats worldwide, with angiosperms achieving near-global coverage and dominating grasslands, forests, and croplands essential for human . Examples include cacti in arid deserts and seagrasses in marine environments, illustrating their versatility from xeric to aquatic conditions. In contrast, gymnosperms are more relictual, with cycads persisting in fragmented Gondwanan regions such as , , and parts of , remnants of ancient distributions shaped by . , however, form vast expanses in northern high-latitude forests, while other gymnosperms like gnetophytes occupy semi-arid to tropical niches. This distribution highlights seed plants' pivotal role in terrestrial , with angiosperms driving productivity across continents.

Ecological and Human Significance

Ecological Roles

Embryophytes, collectively known as land plants, dominate on terrestrial ecosystems, accounting for approximately 80% of Earth's total , primarily through that converts atmospheric into . This process not only sustains vast food webs but also releases oxygen, with terrestrial plants contributing roughly half of the global oxygen production via photosynthetica, balancing marine contributions from . Furthermore, embryophytes play a pivotal role in ; forests alone absorb about 25% of anthropogenic CO2 emissions annually, mitigating forcing through accumulation and storage. In habitat structuring, embryophytes create layered ecosystems that enhance and stability. Bryophytes often act as in primary succession, colonizing bare substrates and facilitating , which paves the way for vascular plants and eventual climax communities dominated by trees in forests. This vertical stratification—ranging from ground-layer bryophytes and to canopy trees—fosters microhabitats, supports diverse , and stabilizes soils against through extensive root systems that bind particles and reduce runoff. Embryophytes also regulate water cycling by intercepting , promoting infiltration, and facilitating , which influences local and regional . Key interactions among embryophytes involve symbiotic relationships, such as mycorrhizal associations with fungi, which extend root networks and enhance nutrient uptake, particularly and , enabling plants to thrive in nutrient-poor soils. Historically, the proliferation of early embryophytes during the era drew down atmospheric CO2 through and burial of organic matter, contributing to and the establishment of ice ages. In contemporary contexts, embryophytes influence climate dynamics profoundly; 2020s research indicates that accelerates warming by releasing stored carbon and altering and , amplifying temperature rises beyond direct effects. Wetland bryophytes, such as mosses, serve dual roles as methane sources through anaerobic decomposition in but also as sinks via associated methanotrophic that oxidize up to significant portions of emitted CH4, modulating feedbacks in these ecosystems.

Economic Importance and Conservation

Embryophytes, encompassing all land plants, form the backbone of global , providing essential food crops such as (Triticum aestivum), which supplies approximately 20% of the world's protein and caloric intake and supports billions in staple diets across temperate regions. Other major crops like and , also embryophytes, contribute to , with wheat alone generating billions in economic value through production, trade, and processing industries. In , —a key vascular embryophyte group—dominate timber supply, accounting for about 72% of global sawnwood production in recent years, fueling construction, paper, and furniture sectors worth hundreds of billions annually. Medicinal uses further highlight their economic value, with compounds like , derived from the bark of the Pacific yew tree (), revolutionizing since its isolation in the and generating substantial pharmaceutical . Biofuels represent another growing sector, where embryophyte biomass such as and woody residues contributes to , reducing reliance on fossil fuels and boosting rural economies through increased farm incomes and job creation in processing facilities. For instance, U.S. biofuel production from plant feedstocks has driven agricultural expansions, adding millions of acres to production and supporting related industries. Conservation efforts for embryophytes face significant challenges, with approximately 37% of assessed plant species threatened by extinction according to the (as of 2024-2), primarily due to habitat loss from and . exacerbates these threats, driving range shifts in sensitive groups like , which have been observed migrating upslope at average rates of about 29 meters per decade, potentially leading to habitat compression at mountaintop limits. Protected areas currently cover about 17.6% of global land and inland waters (as of 2024), leaving a majority of plant diversity hotspots—regions harboring over 50% of unique plant species—underprotected and vulnerable to further degradation. Invasive angiosperms, such as certain grasses and shrubs, disrupt native embryophyte communities by outcompeting locals for resources, altering soil chemistry, and reducing in ecosystems worldwide, complicating restoration efforts. Bryophytes, despite their ecological roles, remain underrepresented in conservation assessments and actions, with only a fraction of their ~ evaluated by the IUCN, leading to overlooked threats from . A 2024 assessment revealed that 38% of the world's tree face extinction risk, underscoring the vulnerability of forest ecosystems. Post-2020 advancements in genomic tools, including CRISPR-based and genomic selection, offer promise for breeding resilient varieties of crops and , enhancing tolerance to and pests while accelerating conservation breeding programs.

References

  1. https://www.digitalatlasofancientlife.org/learn/embryophytes/land-plant-origins/
  2. https://timetree.org/public/data/pdf/Magallon2009Chap11.pdf
  3. https://www.worldfloraonline.org/
  4. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16976
  5. https://www.nature.com/articles/s41586-019-1693-2
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC2707909/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577187/
  8. https://www.cell.com/current-biology/fulltext/S0960-9822(15)01000-3
  9. https://www.nature.com/articles/s41559-022-01885-x
  10. https://doi.org/10.1016/j.cub.2015.08.029
  11. https://www.pnas.org/doi/10.1073/pnas.0603335103
  12. https://doi.org/10.1111/j.1469-8137.2010.03433.x
  13. https://www.ncbi.nlm.nih.gov/books/NBK9980/
  14. https://pmc.ncbi.nlm.nih.gov/articles/PMC1692790/
  15. https://ucmp.berkeley.edu/glossary/gloss8botany.html
  16. https://pmc.ncbi.nlm.nih.gov/articles/PMC2686025/
  17. https://pmc.ncbi.nlm.nih.gov/articles/PMC3762664/
  18. https://www.sciencedirect.com/science/article/pii/S096098221100666X
  19. https://pmc.ncbi.nlm.nih.gov/articles/PMC7065165/
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC9434249/
  21. https://pmc.ncbi.nlm.nih.gov/articles/PMC3394659/
  22. https://passel2.unl.edu/view/lesson/920a6340a995/3
  23. https://pmc.ncbi.nlm.nih.gov/articles/PMC5462059/
  24. https://www.pnas.org/doi/10.1073/pnas.1323926111
  25. https://www.cell.com/trends/plant-science/fulltext/S1360-1385(12)00217-8
  26. https://www.science.org/doi/10.1126/science.abj2927
  27. https://pubmed.ncbi.nlm.nih.gov/20731783/
  28. https://www.cell.com/current-biology/fulltext/S0960-9822(21)01028-9
  29. https://www.sciencedirect.com/science/article/pii/S0960982219315957
  30. https://www.pnas.org/doi/10.1073/pnas.1604787113
  31. https://www.nature.com/articles/s41467-022-35085-9
  32. https://www.academic.oup.com/jeb/article/35/5/5/7317818
  33. https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0490
  34. https://www.tandfonline.com/doi/full/10.1080/23818107.2018.1505547
  35. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2013.00345/full
  36. https://www.journals.uchicago.edu/doi/full/10.1086/686242
  37. https://royalsocietypublishing.org/doi/10.1098/rstb.2014.0343
  38. https://www.nature.com/articles/ncomms1831
  39. https://ucmp.berkeley.edu/carboniferous/carboniferous.php
  40. https://ucmp.berkeley.edu/permian/permian.php
  41. https://pmc.ncbi.nlm.nih.gov/articles/PMC6452062/
  42. https://www.cell.com/current-biology/fulltext/S0960-9822(20)30418-8
  43. https://villarreal-lab.ibis.ulaval.ca/wp-content/uploads/sites/6/2023/11/Bechteler_etal_2023_AJB.pdf
  44. https://www.nature.com/articles/s41588-025-02325-9
  45. https://www.sciencedirect.com/science/article/pii/S0960982221010289
  46. https://pmc.ncbi.nlm.nih.gov/articles/PMC9630106/
  47. https://onlinelibrary.wiley.com/doi/10.1111/j.1096-0031.2006.00089.x
  48. https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.16874
  49. https://pmc.ncbi.nlm.nih.gov/articles/PMC8075897/
  50. https://bsapubs.onlinelibrary.wiley.com/doi/10.1002/ajb2.16249
  51. https://www.tandfonline.com/doi/full/10.1080/07352689.2018.1482396
  52. https://pmc.ncbi.nlm.nih.gov/articles/PMC3448429/
  53. https://pmc.ncbi.nlm.nih.gov/articles/PMC9316050/
  54. https://ucmp.berkeley.edu/plants/lycophyta/lycophyta.html
  55. https://courses.botany.wisc.edu/botany_940/05Frontiers/papers/9Pryer.pdf
  56. https://phycolab.ua.edu/wp-content/uploads/2018/06/PTERIDOPHYTES-II.pdf
  57. https://pmc.ncbi.nlm.nih.gov/articles/PMC9363647/
  58. https://pressbooks.umn.edu/introbio/chapter/plantsangiosperms/
  59. https://www.pnas.org/doi/10.1073/pnas.97.24.12939
  60. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1296&context=envstudtheses
  61. https://www.nhm.ac.uk/our-science/research/projects/plants-under-pressure/bryophytes.html
  62. https://stri.si.edu/story/bryophytes
  63. https://onlinelibrary.wiley.com/doi/full/10.1111/jvs.13136
  64. https://biolres.biomedcentral.com/articles/10.1186/s40659-019-0251-6
  65. https://www.anbg.gov.au/bryophyte/ecology-arid.html
  66. https://www.britishbryologicalsociety.org.uk/learning/about-bryophytes/
  67. https://www.nature.com/articles/s41467-023-40863-0
  68. https://www.nytimes.com/interactive/2022/02/21/headway/peat-carbon-climate-change.html
  69. https://bioone.org/journals/the-bryologist/volume-110/issue-4/0007-2745%282007%29110%255B595%253ADIBAR%255D2.0.CO%253B2/Desiccation-tolerance-in-bryophytes-a-review/10.1639/0007-2745%282007%29110%5B595:DIBAR%5D2.0.CO%3B2.short
  70. https://www.researchgate.net/publication/318156259_Ecology_of_desiccation_tolerance_in_bryophytes_A_conceptual_framework_and_methodology
  71. https://tracyherbarium.tamu.edu/collections/meet-the-specimens/bryophytes/
  72. https://www.nature.com/articles/srep29156
  73. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2025.1539513/full
  74. https://www.amerfernsoc.org/about-ferns
  75. https://basicbiology.net/plants/ferns-lycophytes/lycophytes
  76. https://www.britannica.com/plant/lower-vascular-plant
  77. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1178603/full
  78. https://pubmed.ncbi.nlm.nih.gov/29645092/
  79. https://royalsocietypublishing.org/doi/10.1098/rspb.2018.1012
  80. https://www.mobot.org/mobot/research/apweb/
  81. https://www2.tulane.edu/~bfleury/diversity/labguide/gymangio.html
  82. https://www.conifers.org/zz/gymnosperms.php
  83. https://pressbooks.umn.edu/ecoevobio/chapter/plantsseeds/
  84. https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.19010
  85. https://www.pnas.org/doi/10.1073/pnas.1711842115
  86. https://oceanservice.noaa.gov/facts/ocean-oxygen.html
  87. https://sos.noaa.gov/catalog/datasets/ocean-atmosphere-co2-exchange/
  88. https://www.biologydiscussion.com/biotic-community/succession-in-plant-communities-ecology/51876
  89. https://nativeseedgroup.com/resources/blog/how-do-plants-help-in-erosion-control
  90. https://www.sciencedirect.com/science/article/pii/S0009254120302047
  91. https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15158
  92. https://www.nature.com/articles/s41467-024-51324-7
  93. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JG003053
  94. https://www.fao.org/4/y4011e/y4011e04.htm
  95. https://www.ers.usda.gov/topics/crops/wheat/wheat-sector-at-a-glance
  96. https://www.sciencedirect.com/science/article/abs/pii/S1389934120306626
  97. https://www.cancer.gov/research/progress/discovery/taxol
  98. https://nap.nationalacademies.org/read/13105/chapter/6
  99. https://pmc.ncbi.nlm.nih.gov/articles/PMC11938799/
  100. https://www.iucnredlist.org/resources/summary-statistics
  101. https://www.science.org/doi/10.1126/science.1153657
  102. https://www.unep.org/resources/report/protected-planet-report-2024
  103. https://www.nature.com/articles/s41467-021-21914-w
  104. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.13656
  105. https://iucn.org/resources/publication/mosses-liverworts-and-hornworts-status-survey-and-conservation-action-plan
  106. https://iucn.org/press-release/202410/more-one-three-tree-species-worldwide-faces-extinction-iucn-red-list
  107. https://biolres.biomedcentral.com/articles/10.1186/s40659-024-00562-6
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