A moss is a flowerless, spore-producing plant - with the spores produced in tiny capsules. The introduce WHAT IS A BRYOPHYTE? page detailed that bryophytes have actually a gametophyte stage and also a sporophyte stage. The spore capsule, frequently with a supporting stalk (called a seta), is the sporophyte and also this grows from the gametophyte stage.

You are watching: Mosses are _____.

friend will frequently see the statement the a moss gametophyte is composed of pipeline on stems. That statement is so close to the whole truth that it"s no surprise it"s so typically used.

when a moss spore germinates it an initial develops a protonema. This is a filamentous to sheet-like expansion form, frequently with a solid resemblance come an algal nest or a fern prothallus. In due course one or much more stems flourish from the protonema and leaves construct on the stems, offering rise come one or more leafy-stemmed plants. In almost all moss species, the protonemata are ephemeral, v the leafy-stemmed tree the persistent and dominant expansion form. Yet there room exceptions. In some types the protonema is persistent and the leafy part is ephemeral. The ax gametophore is provided for the stems-and-leaves part and the protonema and also gametophore together make up the gametophyte. Now, as currently noted, in practically all varieties the protonema is ephemeral and insignificant when contrasted with the leafy-stemmed growth. So the leafy-stemmed component is the gametophyte in the great majority that species. It currently becomes clean why that reality is frequently generalized to the statement the the gametophyte in every mosses is leafy-stemmed. For much more about the early on development, watch the LIFE bicycle SECTION. In contrast to the case in mosses, a liverwort protonema is rudimentary.

The aim of this web page is merely to describe the features you have the right to see in a moss - in both the gametophyte and also sporophyte stages. Girlfriend will see some, but by no method all, the the variety in moss gametophytes and sporophytes. This page gives review of the features uncovered in mosses and there are web links to an ext details on several of the topics.

while the to know of mosses frequently requires the use of a microscope, you can learn a lot simply by using your eyes and also a handlens the magnifies 10 times. In the reference switch you’ll find some books with color photographs of Australian mosses. Looking through them will provide you a great introduction to moss diversity.

The complying with references are an extremely useful for more detail around this an excellent diversity, indigenous the macroscopic see to the microscopic level. Lot of the following information top top this page has actually come from these books.

prior to going top top it’s worth noting that you could confuse mosses through leafy liverworts (which additionally have a leaves-on-stems gametophyte stage). However, once you’ve check out this page and also the WHAT IS A LIVERWORT? page, girlfriend will have all the info to let you tell the 2 apart. Because that convenience, the distinguishing features of every the bryophytes room summarised on the web page that allows you answer the question: i m sorry BRYOPHYTE IS IT?

Moss gametophytes

if it might be true to say the a moss gametophyte has "stems and also leaves", that statement pipeline a many unsaid. There is a lot of of intricacy and variety in this ”stems and leaves" plants.

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Ptychomnium aciculare, showing stems

Stems

Moss stems room generally relatively weak and, if free-standing, fairly short. Stem colour varies from green to shades of brown, because that example, Ptychomnium aciculare. Stems are often green as soon as young, with chlorophyll in the cells.

The mosses in the families Dawsoniaceae and also Polytrichaceae carry out striking exceptions to the general rule proclaimed at the beginning of the vault paragraph. Within these families the trunk are fairly firm, through the plants being upright and also quite robust. In this picture of a Dawsonia you can see the brown stems rather clearly. Polytrichum or Dawsonia plants deserve to be rather tall, through the free-standing tribe of some varieties growing to over 60 centimetres in height. For this reason it is not surprising that civilization often mistake these mosses because that herbaceous flowering plants. Though the stems in the Dawsoniaceae and Polytrichaceae are fairly firm, castle contain no lignin and are no woody.

Two expansion forms - tufty and trailing

over there are basically two development forms because that moss plants. In one the stems are basically erect, with simply one upright stem every plant or v the early erect stem producing some branches, depending on the types , giving the individual tree a tufty or shrubby appearance. In the other growth form the moss will have mostly trailing stems. If the stems cling come the substrate the in its entirety appearance, to the nude eye, will be that a creeping tree however in some species they hang, nearly curtain-like, indigenous branches . The rolling mosses are frequently highly branched v the branches cultivation along the substrate - yet many such varieties also create short, upright branches. Branches build from surface cells in the originating stem and also in most mosses branches space simple, single outgrowths native the originating stems. In Sphagnum girlfriend will check out branches developing in fascicles. Within together a fascicle, few of the branches will certainly be stout and also spreading, while others space slender and also drooping.

In varieties with one upright growth type the stems might be really short (almost non-existent) to quite long - as already noted for part Dawsonia species. If over there is just a very rudimentary stem the plant will certainly look like a bunch of leaves cultivation from simply a single point. In genera choose Polytrichum and Dawsonia the individual plants are typically just single stems, with branching rare. Among the upright mosses there are the so-called "dendroid" mosses, which have actually a spread of branches atop a vertical stem . The word "dendroid" way "tree-like" and it"s straightforward to see how apt that term is. In some cases, instead of branches in all directions, there"ll be a fan-like spread of branches. You"ll additionally see such mosses referred to as "umbrella mosses" - an equally apt descriptive expression.

there are plenty of erect-stemmed species of moss wherein the plants grow an extremely closely together in mat-like or cushion-like colonies. In such situations it deserve to be difficult (or even impossible) come make the end the separation, personal, instance plants, uneven you closely tease personally a tiny section the the mat or cushion to view what it’s written of. Here’s a photo of a large colony the a silvery-green moss, Bryum argenteum and here’s a closer watch of the upper surface ar of such a moss nest when wet . You can see a somewhat cobblestone-like surface. If you take it a very small sample from the colony and also look at it side-on you check out this . What you see in the final photo is a small number of individual plants, packed together really tightly.

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Leptostomum macrocarpum, reflecting dead material below

In the instance of the cushion-like growth, lot of the cushion may be written of dead product (photo right). Together the trunk grow, the older pipeline (lower down on the stem) die, leaving a living environment-friendly layer atop a mass of brown, dead material. That brown section will it is in a mix of rhizoids, dead leaves and stems, and also other organic issue that may have actually been trapped through the plants consisting of the moss-cushion. You have the right to still make out some leaves in that mass the brown. Together the stems proceed to grow, more and much more dead material will accumulate. Together largely-dead cushions are an ext characteristic the moist areas, whereby they can prosper to a significant size. That is typical to check out sizable environment-friendly cushions, on absent or trees because that example, in moist habitats.

instead of farming in cushions, girlfriend can likewise get simple-stemmed varieties where the plants grow separately from each other. Climate they look like many small, green fingers poking up from the soil.

In a creeping moss there might be short, irpari branches that grow away from the substrate however such branches are just off-shoots indigenous the creeping stems. Over there are also moss types that create long, trailing stems yet where (apart native a tiny attachment area) the stems don’t cling come anything. In such instances you deserve to see a pendulous, curtain-like growth, such together that the Papillaria flavolimbata .

In some varieties of clinging, trailing-stemmed mosses the quick branches that prosper away indigenous the substrate might be really easy to see whereas the clinging stems may be difficult to see. Because that example, the upright branches might be so numerous as to hide the trailing stems or possibly it’s a types with very couple of leaves top top the clinging stems, so making it harder to realize over there is stem there. Or it may be that the main stems are growing in bark cracks or are hidden by sheet litter. In every such cases, unless you look at carefully, you could easily wrong the different upright branches the the one, climb moss plant as plenty of individual tree of a tufted species.

In Gigaspermum repens there is a creeping, mostly leafless, secret stem the is seldom seen. All the is visible above ground room short, erect leafy branches (1 come 3 millimetres tall). It would certainly be straightforward to think that each such leafy branch together a separate plant.

Rhizoids

every mosses have actually rhizoids. These room anchoring structures, superficially root-like, yet without the absorptive attributes of true roots. Moss rhizoids are constantly multi-celled and often branched, whereas liverwort rhizoids are mostly single-celled and rarely branched. Rhizoids are existing at the protonemal stage. Once stems have emerged rhizoids happen at the bases of trunk (in the tufty species) or follow me the trunk (in the rolling mosses). While all mosses have actually rhizoids, some species may be dense with rhizoids while on others the rhizoids space sparse .

Moss rhizoid systems deserve to be extensive. Over there are instances of floor mosses wherein the above-ground plant may be only a centimetre or therefore in height - but where the rhizoid system reaches 3 or an ext centimetres into the soil. Rhizoids aren"t roots and don"t conduct water and nutrients internally, but a fixed of rhizoids can conduct water externally through capillary action. In some varieties the rhizoids space wound together, virtually rope-like, and such strands are an extremely effective at relocating water by capillary action.

pipeline

In a dry moss plant the pipeline are commonly folded right into or curled around the stems. In such cases the pipeline unfold or uncurl once the plant becomes wet. Thus a moss have the right to look quite various in the wet and also dry states. However, over there are types where, even in a moist plant, the leaves still clasp the stem.

The individual leaves are small, usually from fifty percent a millimetre to 3 millimetres long. They are constantly attached straight to the stem, never with a quick stalk. In many genera the leaves are simply one cell thick, making lock translucent. In countless such genera the leaves space thickened along their long main axes. Such a thickening is dubbed a nerve or costa. There are a few genera (such together Leucobryum and Sphagnum) wherein the leaves are number of cells thick. Moss leaves generally taper to the tip (though the tapering might be suddenly or gradual). The guideline may proceed as a lengthy hair-like extension, dubbed a hairpoint.

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Campylopus introflexus, mirroring hair points

The photo (right) shows a nest of Campylopus introflexus, a common and widespread varieties in Australia. In this varieties each leaf has actually a hairpoint and the photograph shows the hairpoints quite clearly. Leaf bases might vary, depending upon species, gift anything from much narrower to much broader than they space at mid-leaf, and also they might be lengthy or short in relation to width. The leaves frequently have smooth or virtually smooth margins. The margins may be toothed however you don"t obtain the heavily split leaves the are common in the irpari liverworts.

different parts the the tree may have actually different types of leaves. Because that example, in numerous trailing species the pipeline on the upright branches are different to those on the rise stems. In plenty of mosses, whether rolling or tufty, the leaves that surround the egg and also sperm producing organs different from the other leaves on the plant.

There"s much more about bryophyte leaves in the leaf SECTION.

Antheridia and also archegonia

The male and female gametes (eggs and sperm) are developed on the gametophyte (in distinct structures called antheridia and archegonia, respectively) and also a fertilized egg will develop into a sporophyte. Hence the spores are part of the sex-related reproduction cycle. There"s much more about this in the REPRODUCTION SECTION. Mosses can be split into two wide groups, relying on where the archegonia space produced. In the acrocarpous mosses the archegonia are created at the end of the main stems. In the pleurocarpous mosses the archegonia are created on quick side-shoots, not on the main stems.

Moss sporophytes

A moss sporophyte is composed of a spore-containing capsule, maybe sitting atop a stalk (called a seta). In this photograph you deserve to see numerous brownish sporophytes (the stalked spore capsules) that have actually grown indigenous the greenish, leafy-stemmed gametophyte. The sporophyte"s development is debated in the SPOROPHYTE advancement SECTION.

In virtually all moss species the capsule has actually a well-defined mouth at the finish opposite the stalk or the suggest attaching the capsule come a stem. When there is a mouth, the spores space released through that mouth. There is a really small variety of mouth-less mosses - such as types of the genus Andreaea. This genus is commonly found in polar areas and also in sub-alpine to alpine areas (and also alpine areas in the tropics). The capsules that Andreaea execute not have actually mouths. Rather they open up by slits in the political parties of the capsules. In part genera (such as Archidium) the capsules have neither mouths no one splits in your slits in their sides. Instead, the capsules rupture irregularly.

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The maturation spore capsule might (depending ~ above species) hang down, stick up - or be organized at any type of angle in between. The way the capsule opens (mouth, side slits, irregular rupturing) and also the orientation that the capsule play essential roles in the method in which spores space released and also there"s an ext about spore dispersal in the in DISPERSAL SECTION.