Lab 8 - Primitive plants -Bryophytes,Ferns and also Fern Allies
As we pass from mosses come ferns, we check out a gradual change fromprimitiveto contemporary traits. There are two major trends friend should emphasis on intoday"slab. The very first is a shift in life cycles, the 2nd is a changeinbasic inner structure.
You are watching: Moss is a type of ________. angiosperm gymnosperm fungus fern bryophyte
First, all plants undergo an alternation that generations,between a haploid gametophyte stage and a diploid sporophytestage. In the many primitive plants, prefer mosses, the gametophyte isdominant(i.e. It"s big and green). In greater plants like ferns and also fern allies,the sporophyte phase is dominant. Gametophytes produce gametes (spermandeggs) in a one-of-a-kind structure dubbed a gametangium (-ia), whilesporophytesproduce spores in a one-of-a-kind structure referred to as a sporangium(-ia).
Second, all plants need to get water to their cells.Primitivebryophyteslike mosses and liverworts space so small that they can rely ~ above diffusionto move water in and also out of the plant. Mosses have a couple of strands ofwaterconducting tissue in their central stem, yet nothing favor the large andwell organized network of pipe in tracheophytes, or "tubeplants".The vascular tissues in the much more advanced ferns and also "fernallies"are consisted of of xylem and also phloem, which command water,nutrients,and food transparent the plant body. We"ll look at this tissues in alaterlab.
Bryophytes likewise need a moist setting to reproduce. Theirflagellatedsperm must swim through water to reach the egg. For this reason mosses andliverwortsare limited to moist habitats. There are no mosses in the desert.Butmosses room surprisingly resistant to dry up, and also can survive underveryharsh conditions. Mosses space the many abundant plants in both theArcticand the Antarctic. Asexual reproduction in bryophytes is accomplishedbyfragmentation or by small vegetative "sprouts" referred to as gemmae,whichform in special tiny structures dubbed gemmae cups.
Mosses and also liverworts space lumped with each other as bryophytes,plantslacking true vascular tissues, and sharing a variety of other primitivetraits. They likewise lack true stems, roots, or leaves, despite they havecellsthat do these basic functions. The leafy environment-friendly plant that us seewhen us look at a moss or a liverwort is yes, really the gametophyte,which is the leading stage in all bryophytes. The sporophytesofbryophytes carry out not have actually a free-living existence. They grow directly outof the fertilized egg in the archegonia, and remain dependence on theparentgametophyte for your nutrition.Characteristics of Divisions
Division Bryophyta - (9,500 sp.) - mosses, Mnium, Sphagnum
Mosses come in two basic types, a cushiony type, with erect stalks,and a feather type, which forms flattened carpet of low-lying and highlybranched moss plants. In both cases, the leafy green gametophytes aredioeciousThey deserve to be masculine plants, through antheridia at the optimal of the plant, orfemaleplants, with archegonia at the top. Remember the these gametophytesarealways haploid (1N) plants.
Sperm are produced within each antheridium, and also an egg ineacharchegonium.Because the plant is currently haploid, this gametes deserve to be produced bymitosis,simple cabinet division. The sperm swims come the archegonia v a thinfilm of water, drawn by a chemical attractant produced by the femaleplant,then swims down the neck of the archegonia come the egg. A great morningdewis much more than sufficient water for the sperm to swim. When the spermentersthe archegonia, it fuses v the egg. The 2N zygote creates into adiploidsporophyte plant, a small stalk the grows straight out that the height ofthearchegonium. This stalk is initially green, and also photosynthetic, butlaterturns brown and also becomes basically a parasite ~ above the femalegametophyte.
The sporophyte plant is composed of a stalk, and a tiny capsuleon the top. In ~ the capsule, cell undergo meiosis come producetetradsof haploid spores. Once the capsule is ripe, its hinged lid oroperculumopens up, and also the spores are quickly distributed by wind and also water. Thesporesgerminate right into a tiny eco-friendly thread, i beg your pardon looks like a simple strand ofgreen algae. This similarity is one an ext clue the bryophytes aredescendedfrom green algae. This early threadlike phase is dubbed the protonema(= an initial thread, plural = protonemata, favor stigma/stigmata). The newadultgametophytes grow from a tiny bud that develops on the protonema.Eventuallythese gametophytes will prosper to produce gametes, and the totality cyclewillstart over again. Mosses can likewise reproduce asexually by fragmentationor by growing tiny vegetative buds called gemma, which have the right to break offand prosper into a brand-new plant .
While bryophytes in basic are more interesting than important, inthe usual sense, a conspicuous exemption are mosses that the genus Sphagnum.Sphagnummoss forms dense mats which end up being compressed right into peat, which have the right to beusedas fuel, back it’s an extremely smoky. Peat likewise contains other plants suchas reeds, that thrive amid the sphagnum. In dried form, peat moss isremarkablyabsorbent and, and has been offered for diapers, because that enriching negative gardensoils, and as a field dressing for wounds. Whereas noodle absorbs 4-6timesits dry weight, dried sphagnum have the right to absorb 20 time its very own weight influids!Peat bogs are very important and interesting ecosystems. Sphagnummosses significantly increase local acidity by publication H+ ions, and the pHof peat bogs deserve to drop to 4 or lower, maybe the many acidic naturalenvironment.Peat bogs cover around 1% the the Earth’s soil surface, an area abouthalfthe size of the united States.
Division Hepaticophyta - (9,000 sp.), liverworts, Marchantia,Conocephalum, Porella
Liverworts have the simplest bodies of every the environment-friendly plants. Thegametophyte,the leading stage, looks choose a flat scaly leaf, with significant lobes.It looks for every the civilization like a tiny flattened liver, therefore thescientificname hepatico-phyta = liver plant. During the center Ages, thissimilaritycaused medical professionals to prescribe liverwort for diseases of the liver.Accordingto the theory of Signatures the Creator had actually designed every one of nature,includingplants, with our welfare in mind. People thought that plants had actually beenintentionally designed come resemble the organs of the human body they weresupposedto heal! therefore liver-wort, wyrt being the Anglo-Saxon word for herb.Theshape of the liverwort was the signature the the Creator in nature. Canyou guess what walnuts were supposed to cure ? (diseases the thebrain)
Liverworts share the basic properties that bryophytes, however are notveryclosely regarded mosses or hornworts. Countless botanists think they mayhaveevolved independently, native a various group of environment-friendly algae. Because that onething,liverworts don’t save food as starch but as oils. If you acquire theaquaticliverwort Porella in lab, take it a sniff the the jar, but not toodeep!It smells that rancid oils, oils the went a tiny funky when the plantwas gift shipped. One more characteristic distinct to liverworts is theirlack the stomata, i beg your pardon are found in all various other plants, including mossesand hornworts.
In many species of liverworts, such as Marchantia, the oneyouwill most likely see in lab, the antheridia and also archegonia room not ontopof the plant, however hanging under from the underside of odd littlestructuresthat look prefer tiny umbrellas. (These umbrella-shaped structures arecalledthe antheridiophore and archegoniophore). The bi-flagellated spermswimsto the egg, and fertilization takes place to form a diploid (2N)zygote.The small diploid sporophytes, which stay attrached come the parentplant,have a very basic structure. Meiosis in ~ the sporophyte to produce anumber of haploid spores. This spores are surrounded by curious longandtwisted moist cells referred to as elaters. As soon as the capsule dries and bursts,the elaters twist and jerk approximately in a method that scatters the spores inall directions. Liverworts can additionally reproduce asexually by means ofspecialstructures referred to as gemmae cups. These little cups can be easilyseenon the surface of the plant. Each gemma cup consists of a number of tinyplantletscalled gemmae, and a solitary drop of water will disperse them. Theselittlevegetative “clones” will certainly then prosper into a new gametophyte.
Division Anthocerophyta - (100 sp.), hornworts, Anthoceros
The green gametophytes the the hornwort look an extremely much prefer aliverwort.But their tiny sporophytes more closely resemble those of mosses. Thesporophytes thrive out of the gametophyte, and also look like a tiny uprighthorn. Favor mosses, hornworts have stomata, and also so are more than likely morecloselyrelated come mosses and other plants than to the liverworts they matresemble.These plants room symbiotic through the cyanobacteria Nostoc. Thecyanobacteriafixes nitrogen because that the hornwort.Taxonomy
Division Bryophyta - mosses (Mnium, Sphagnum; fr.Gr.bryon= moss)
Division Hepaticophyta - liverworts (Marchantia,Conocephalum,Porella; fr.Gr. Hepato = liver)
Division Anthocerophyta - hornworts (= Anthocerotophyta; Anthoceros;fr.Granthos = flower, keras = horn)Terms alternation the generations gametophyte gametangium (-ia) archegonium (-ia) antheridium (-ia) sporophyte sporangium (-ia) spore capsule protonema vascular mechanism gemmae gemmae cupTo Do and also View
Examine the living mosses top top display. Notice the tiny capsuleson top of the tiny sporophytes. Mosses generally flourish in among twogrowthtypes: cushiony moss and also feathery moss.
Examine slides the the antheridia and also archegonia. The sausageshaped antheridia develop sperm, and also the flask shaped archegoniaproduces eggs.
Examine slides that the moss capsule, and identify the spores.
Examine slides that the protonema. What type of algaedoesit remind you of? This same is added evidence that greenalgaegave climb to all higher plants.
Examine the terrestrial liverworts Marchantia and Conencephalum(oneor both have to be top top display). How does their expansion habit differ fromthat of the mosses? deserve to you see any type of gemmae cups top top the uppersurfaceof these plants?
Examine slides the the liverwort Marchantia.
Examine the aquatic liverworts prefer PorellaandRiccia(one or both must be top top display). An alert how they different from themoreterrestrial forms of liverwort.
Look in ~ the kept liverworts, and also observe their distinctreproductive frameworks (they watch like little green umbrellas). Howdoestheir life cycle differ from mosses?
Examine slides of the hornwort Anthocerophyta.Things to Remember
Know the life bicycle of the moss in detail, and be able torecognizethe various stages.
Hint: Be certain you understand the basic life cycle ofplants,and have the right to tell which stages space haploid gametophytes (1N) or diploidsporophytes(2N). We"ll find out several life cycles in lecture and also in rap (moss,fern,pine, flowering plant), but every one of them space variations ~ above the samebasictheme.Ecological, Evolutionary, and Economic Importance
Mosses are necessary in landscaping and gardening, especially peatmoss(Sphagnum).
Peat moss (Sphagnum) has been used historically as dressingsfor wounds.
Peat moss deserve to be used as fuel.
Mosses room the most primitive living land plants.
Hornworts contain symbiotic nests of the cyanobacteria Nostoc.
shining society moss
Introduction come Tracheophytes - Ferns and Fern Allies
Tracheophytes (vascular plants) perfect the conquest of theearth’s surface started by the more primitive bryophytes. Simply as theevolutionof spores to be the crucial to the invasion of the land surface ar bybryophytes,the invention of complicated vascular tissues let tracheophytes completetheconquest of dry land. There are around 250,000 varieties of vascularplants,grouped in ripe divisions. Tracheophytes all have actually a well developedroot-shootsystem, with highly devoted roots, stems, and also leaves, andspecializedvasculartissue (xylem and also phloem) that duty like miniature tube toconductfood, water, and nutrients transparent the plant. Since ferns and fernallies posses true vascular tissues, castle can flourish to be much largerandthicker 보다 the bryophytes.
The ferns and also fern allies (non-seed tracheophytes) mark two majorevolutionarystrides. In these and in all an ext advanced plants, the leafy environment-friendly diploidsporophyte now becomes the dominant stage. The small gametophytemay be either autotropophic (like the fern prothallus) orheterotrophic(like the gametophytes of some lycopsids), and also is generally free livingand elevation of the parental sporophyte. Unlike the vascularsporophytes,the gametophytes have actually no vascular organization at all. This gametophytes aretherefore an extremely small, and also develop best in moist areas, where they canabsorbwater directly from their surroundings.
Like the bryophytes, ferns and fern allies are still restricted tomoisthabitats. Your flagellated sperm require a thin film that water come swimbetweenthe antheridium and also the archegonium. And also when the baby sporophyte growsup native the gametophyte, that is exposed come desiccation (drying up). Thisbasic strategy that a free-swimming sperm and a non-motile egg is sharedby plants, animals, and also algae. It makes sense, because it way onlyoneset the gametes needs to make the perilous journey exterior of theorganism.
ground pine (Lycopodium) reflecting strobili
The ferns and also fern allies germinate indigenous spores. This plants aremostlyhomosporous- your spores space identical and also you can"t identify which willgrow into male or female plants. Castle are also monoecious -boththe archegonia and antheridia (male and female reproductive structures)are borne top top the exact same plant. Contrast these primitive vascular plantswiththe much more advanced seeds plants, the gymnosperms and angiosperms, whichgerminatefrom seeds quite than indigenous spores. Seed plants are all heterosporous.It is simple to distinguish the bigger female megaspore fromthesmaller male microspore. The sperm of seeds plants have actually noflagella.They lack antheridia, and only a couple of still have an archegonia. Unlikethemore primitive ferns and also fern allies, seed plants are mostly dioecious,having separate male and female plants.
In numerous of this primitive plants, specific leaves room specializedforreproduction. This modified leaves, or sporophylls, bear thesporangiaat their bases. This sporophylls generally branch out from a shortenedstem,forming a society shaped structure referred to as a strobilus. The pineconeand the flower are intricate variations on this primitive strobili.
There are four departments of non-seed tracheophytes, vascular plantsthat give birth by way of spores, the Psilophyta, Lycophyta,Sphenophyta,and Pterophyta. Before these non-seed tracheophytes evolved, thebryophyteswere the dominant kind of plant life. The evolutionary edge of having amore reliable conducting system, and a well-developed root-shootsystemenabled them to outcompete bryophytes. If you’re lucky sufficient to seegroundpine or various other club mosses farming in the the shade of a large pine tree,thinkfor a moment about how these small plants were as soon as the masters of theplanet,forming substantial forests v trunks native 20 come 100 feet tall!Taxonomy
Tracheophytes (vascular tissue, no seeds)
Division Lycophyta - society moss, quillworts (Lycopodium,Selaginella)
Division Sphenophyta - horsetails (Equisetum; fr.L.equus= horse)
Division Psilophyta - whisk fern (Psilotum)
Division Pterophyta - true ferns (Pteris; fr.Gr.pteridion= tiny wing)Terms homosporous heterosporous megaspores microspores rhizomes sporophylls strobilus (-i) sori indusium (-ia) prothallus fiddleheadsCharacteristics the Divisions
Division Psilophyta - (fr Gr. Psilo = smooth), whiskferns,Psilotum
There are just two living genera the whisk ferns, single survivors that alarge and widespread group of beforehand land plants. In enhancement to thelivingDivision Psilophyta, the psilopsids, there are two extinct divisions ofprimeval vascular plants. The primitive whisk ferns resemble theseextinctpioneers in countless ways. They room the just living vascular plants thatlacka root-shoot system, a characteristic lock share through both extinctDivisionsof genealogical vascular plants. Some current molecular evidence suggeststhatone, or also both, the the living genera that psilopsids may actually bemoreclosely pertained to ferns, prefer a fern that has reverted to moreprimitivetraits. If this is true, climate Psilophyta will sign up with the ranks of thenumerousextinct divisions of plants.
Psilopsids are discovered in tropical and also subtropical areas, and also occursthroughoutthe southern US. Ns once uncovered one farming on my back porch under theleavesof a spider plant. Whisk ferns room a typical weed in greenhouses alloverthe world. They are simple green upright stems, v dichotomousbranching.They have actually no leaves, and also no true roots. The outer tissues the the stemdoall the photosynthesizing. A part of the stem referred to as a rhizome runsalong the ground, or just listed below it. A rhizome is a horizontalstemthat spreads the tree around. Roots grow out the bottom of therhizome,and a new plant can arise at the same allude from the top.
The green stem-like tree is the diploid sporophyte, the dominantstagein the life cycle. In the tiny sporangia (bright yellow) the formalongthe upper stems, the spore mom cell creates haploid spores by meiosis.Their gametophytes room tiny tiny thread-like underground plants thatlack chlorophyll, and also live as heterotrophs in the soil, feather andactingmuch prefer a tiny fungi. It actually consists of a symbiotic fungi, thesamemycorrhizae that live in the rhizomes the the adult sporophyte.
Division Lycophyta - (1,000 sp., fr. Gr. Lycos=wolf), clubmosses,quillworts, Lycopodium (podus=foot)
Their are only five living genera that lycopsids, but at one time fromthe distant Devonian, around 400 mya, well into the Carboniferous, theywere the dominant form of vegetation on the challenge of the Earth. Now theyare reduced to a shadow of their glorious past, inconspicuous littleplantsin the forest understory. The tropical species are small epiphytes(plantsthat flourish on other plants).
Their roots prosper from one-of-a-kind underground stems dubbed rhizomes, asdo most of this primitive tracheophytes. In some species thesporophyllsare mixed in through the scale-like leaves. In countless species, thesporophyllsare organized into strobili, for this reason the usual name the “club moss”. Thesperm swim under the strobilus to the archegonia, and the zygote thatformsis kept in the cone, i m sorry ripens and also falls come the ground. Thegametophytesare independent and also free-living, They room curious creatures that lookandact nothing like their sporophyte parents. They deserve to be eitherheterotrophicor autotrophic, and also usually have actually a symbiotic fungi linked withthem.Many the the lycopsids space heterosporous. Selaginella is a goodexampleof a heterosporous plant.
Division Sphenophyta - (15 sp., one genus, fr. Gr.sphen=wedge),horsetails, Equisitum
In waste places, disturbed locations like trails and also railroad beds, andin strange corners of fields and forests you can find another little plantquietly dreaming that its former splendor, the horsetail. Horsetailsappearedin the late Devonian, and also were among the leading forest trees forhundredsof millions of years. Only one genus of Sphenophyta quiet exists, thegenusEquisetum,and it may be the oldest living genus of plants on earth. Horsetailstoweredamong the Carboniferous forests, getting to heights the 30-60 feet. Muchofthe coal deposits we manipulate for fuel today were formed from horsetailsand various other trees during the Carboniferous, towards the end of thePaleozoic.
Horsetails have actually true roots, stems, and leaves, despite the pipeline arelittle an ext than flattened stems. Your hollow, ribbed stems arejointed,kind of choose a stalk the bamboo, and a whorl of leaves arises in ~ eachjoint.The plants are spread vegetatively by rhizomes. The stems feeling veryrough,because the epidermal tissues space impregnated with tiny seed ofsilica(sand). This more than likely helps defend the plant against herbivores. Theserough stems make this plant best for pioneer women to usage forscrubbingpots and also pans, therefore its other common name, “scouring rush”.
The environment-friendly plant we see is the diploid sporophyte generation. Thestalkscan be highly branched vegetative stalks, which in reality look likehorsetails, or straight unbranched reproductive stalks, which are tippedwitha huge strobilus include the sporangia. The homosporous sporesdevelopinto a teeny-tiny eco-friendly gametophyte, simply a few mm long, the lookslikethe gametophyte the a fern. The gametophyte is haploid, free-living, andautotrophic.
Division Pterophyta - (12,000 sp., fr. Gr. Pteridion=littlewing),ferns
Ferns probably developed from the psilopsids, at some point in theDevonian,relatively beforehand in land tree evolution. Castle are an extremely abundant anddiverse, varying in size from a solitary centimeter to tree 24 meterstallwith 5 meter fronds. Ferns have actually been far better competitors v seedplantsthan other seedless vascular plants, and also are a conspicuous part of thelandscape throughout the world, but especially in the tropics, where75%of their 12,000 varieties occur.
Ferns are fairly advanced plants, v true roots, stems andleaves.The tongue of the fern is called a frond, and also the little individualleafletsare dubbed pinnae. Ferns have actually true leaves, what botanists callmacrophylls.While the leaves of an ext primitive plants, which space calledmicrophylls,are simply expansions of the epidermis the the stem, the pipeline of fernsand greater plants were created as a web of tissue extended betweensmallterminal branches. The pipeline of higher plants, and also the modifiedleaves that make up the jaw cone and also the flower.
The life cycle of the fern is common of other non-seed vascularplants.The leafy environment-friendly plant is the sporophyte. Productive fronds developsclustersof tiny sporangia on the underside the the frond. This clusters ofsporangiaare referred to as sori (sing. Sorus). Sori room often protected by atinyumbrella-like cap referred to as an indusium (-ia). Ferns room mostlyhomosporous,though some space heterosporous. The heterosporous state is a moreadvancedcondition, that seems to have progressed independently in numerous groupsofplants.
The haploid spores are created by meiosis inside the sporangium. They ejected in a miniature explosion brought about by the unequal drying ofthealternate thick and also thin-walled cells that line the external surface. Thetop traction slowly ago until the reaches a an essential point and then snapsforward at an incredible speed. In ~ that dimension scale, the expulsion offernspores is one of the many explosive events in nature. The sporesgerminateinto small gametophytes. The little heart shame gametophyte is called aprothallus,literally “first-body” (pl prothalli). The prothallus has no vasculartissue.Its little size lets it rely completely on diffusion. Its tiny rhizoidsareassociated v mycorrhizal fungi. The little prothallus is green, andphotosynthetic, and also bears either antheridia and archegonia, orsometimesboth together, on its upper surface ar (lab slides have both top top sameprothallus).The archegonia are constantly found in ~ the arch of the heart, and also theantheridiaare tucked away among the tiny rhizoids at the various other end. The spermswimsto the egg come fuse right into a diploid zygote. The brand-new sporophyte growsdirectlyout the the optimal of the gametophyte. When it very first begins to uncurl, thefrond looks prefer the scrolled neck that a violin or fiddle, and thisstageof advance is dubbed a fiddlehead.
To Do and also View
Examine the life lycopsids ~ above display. Why are they calledclub mosses? notification that quillworts and also Selaginella are verydifferentin appearance from the society mosses.
Examine slides of Selaginella"s strobilus. Determine megasporesand microspores.
Examine the living horsetails on display. An alert theprominentstrobiliofthe reproductive stalks, and also the bushy growth kind of the vegetativestalks(if available).
Examine the life whisk ferns on display. Psilopsidshave a an easy dichotomous branching pattern. You may see tiny yellowsporangiaon the branches. Whisk ferns absence strobili. These primitive tree areclosely pertained to ferns.
Examine the life ferns ~ above display. Can you see any kind of fiddleheads?Look because that the rhizomes. Rhizomes space modified horizontal stemsbearingroots, that run along or just underneath the ground, and spread fernsandfern allies around.
Examine the living fern prothallus on screen under adissectingmicroscope. Note its characteristic love shape. Part prothalli mayhavea tiny brand-new fern emerging from the notch that the "arch" heart, whereby thearchegoniaarelocated.
Examine slides of the prothallus: uncover the archegonia(can you watch an egg?).
Examine the fern leaflet on display under the dissectingmicroscope.Notice the influential indusia, and also the tiny sporangiapeekingout from beneath. You"ll check out a few groups that sporangia that have losttheirindusium. If you"re lucky, together the warm of the microscopic lense dries out theleaflet, you might see the sporangia eject that spores. However don"tblink- it"s one of the fastest and also most explosive action in nature. Use highpowerto watch the spores.
Examine slides of the sori and indusia; use high powerto watch the spores.Things come Remember
Know the life cycle of the fern. Identify specimens andslidesof the assorted stages.Economic, Ecological, and Evolutionary Importance
Ferns and fern allies are generally responsible for our moderndepositsof coal.
The fiddleheads the some varieties of ferns room edible.
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Ferns are necessary for the florist, gardening and also landscapeindustries.Consider This
Why space all this plants limited to wet habitats?
Which team of protists gave rise to these plants? (How carry out we know?)
Why is the epidermis of the horsetail therefore rough? What does that needprotectionfrom?
All of the fern allies in this lab as soon as towered 50-100 feet or more.What happened?
Links to Explore
Bryophyte taxonomy, images, and more at:
Get info about bryophytes native the Missouri factory Garden at:
Lie down amongst the ferns in ~ the American Fern Society, try theirlengthylist that links:
Basic details on ferns and fern allies, finish with images, courtesyof Texas A&M:
Look for ferns ~ above the "tree the life" at