5.3: Mosses
- Page ID
- 35331
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Mosses, Phylum Bryophyta
Gametophyte Generation
Mosses produce only leafy gametophytes. You can differentiate them from leafy liverworts because the leaves are arranged in a spiral and usually have a midrib-like struture called a costa. Like the other two groups of bryophytes, simple pores on the gametophyte allow for gas exchange (no guard cells, meaning pores are permanently open).
![A group of moss gametophytes](https://bio.libretexts.org/@api/deki/files/26845/Moss_(Dicranum).jpg?revision=1&size=bestfit&width=511&height=383)
![Clustered green, leafy gametophytes. Thin leaves emerge at all angles from each gametophyte.](https://bio.libretexts.org/@api/deki/files/45317/1.jpg?revision=1&size=bestfit&width=652&height=490)
![A close up of part of a moss leaf.](https://bio.libretexts.org/@api/deki/files/45318/2.jpg?revision=1&size=bestfit&width=520)
![A cluster of moss gametophytes.](https://bio.libretexts.org/@api/deki/files/45319/3.jpg?revision=1&size=bestfit&width=656&height=616)
![Labeled long section of a Mnium antheridial head](https://bio.libretexts.org/@api/deki/files/29952/InkedMnium_Antheridial_Head_left_half_LI.jpg?revision=1&size=bestfit&width=608&height=456)
![Mnium male gametophyte, looking down at the splash cup](https://bio.libretexts.org/@api/deki/files/45320/4.jpg?revision=1&size=bestfit&width=611&height=458)
![Long section through a Mnium female gametophyte](https://bio.libretexts.org/@api/deki/files/29953/InkedMnium_Archegonial_Head_2_LI.jpg?revision=1&size=bestfit&width=637&height=480)
![Mnium female gametophyte, with no obvious structures visible](https://bio.libretexts.org/@api/deki/files/45321/5.jpg?revision=1&size=bestfit&width=630&height=700)
Sporophyte Generation
Moss sporophytes have a complex set of structures at the top of a seta. When the sporophyte emerges, it tears off a piece of the female gametophyte's archegonium, leaving a coating called the calyptra. Mosses have a capsule, where the sporangia are housed. This capsule has a lid-like structure called an operculum, which pops off when spores have matured. Depending on the moss, the sporophyte may have a peristome (teeth-like sheets of cells that aid in spore dispersal). True stomata are present for gas exchange.
![Moss sporophytes (with calyptras) emerging from gametophytes](https://bio.libretexts.org/@api/deki/files/26846/Bryophyta_sporophytes.jpg?revision=1&size=bestfit&width=746&height=739)
![A moss sporophyte with an operculum](https://bio.libretexts.org/@api/deki/files/26844/Buxbaumia.jpg?revision=1)
![Moss sporophytes without calyptras, showing the operculum of each](https://bio.libretexts.org/@api/deki/files/27319/Sporophytes_moss_w_operculum.jpg?revision=1&size=bestfit&width=523&height=595)
![A moss sporophyte that still has a calyptra covering the capsule](https://bio.libretexts.org/@api/deki/files/26842/Moss_sporangium_calyptra.jpg?revision=1)
![A moss sporophyte that no longer has a calyptra or an operculum](https://bio.libretexts.org/@api/deki/files/26843/Moss_sporangium_peristome.jpg?revision=1)
Mnium Life Cycle
![Moss life cycle diagram](https://bio.libretexts.org/@api/deki/files/29954/InkedMnium_Life_Cycle_Bryophyta_LI.jpg?revision=1)