1. Kingdom Plantae Phylum Bryophyta Class Muscopsida
Mosses
Kingdom Plantae
Phylum Bryophyta
Class Muscopsida
Eukaryotic
Cellulose and Pectin Cell walls
Open mitosis, phragmoplast cytokinesis
Chloroplasts with chlorophyll a, b xanthophylls, carotenoids
Starch storage
Diplohaplontic (sporic) life history
Homosporous

2. The green plant is the moss gametophyte (haploid).
It uses chlorophyll a and b, xanthophylls, and carotenoids for photosynthesis.
It produces starch for storage of photosynthate.

3. The gametophyte can live in creek beds and dry forests

4. While many tell about mosses needing lots of water, mosses can live on bare rock with virtually no soil.
It is true that they need some rainfall to complete the life cycle and produce the sporophytes (tan color) shown here.
Nevertheless they can tolerate long periods of desiccation.

5. Talk about a difficult climate, here are mosses living on a glacier!

6. The sperm found their way to the egg and syngamy took place.
These haploid green moss gametophytes have produced gametes some time ago.
The sperm found their way to the egg and syngamy took place.
These tan structures are the sporophytes that grow from the zygote.
The diploid sporophyte is dependent upon the haploid gametophyte for photosynthetic products.

7. The morphology of gametophyte and sporophyte assist in moss taxonomy
The morphology of gametophyte and sporophyte assist in moss taxonomy. Meiosis takes place inside the capsule

8. The product of meiosis in the moss capsule is this haploid spore

9. What process is just finishing in the extremely large chloroplast?
The moss spore is a complete haploid cell with normal plant cell structure.
Cell Wall
Cell Membrane
Nucleus
Chloroplast
Mitochondrion
Vacuole
Cytosol
The cell wall is waterproofed with sporopollenin to avoid desiccation
What process is just finishing in the extremely large chloroplast?

10. After distribution on wind to a new environment into good conditions, the spore wall cracks open for germination into a haploid gametophyte produced by mitosis only.

12. The spore cell divides mitotically to produce a haploid multicellular gametophyte.
It is initially filamentous with bright green chlorplasts and gives every appearance of a green alga.
The terms “onotogeny recapitulates phylogeny” comes to mind!
This filamentous plant body is called the “protonema” and the “chloronema” depending upon how far away in time from germination one is looking.

13. Moss protonemata in prepared slides just don’t look so nice.
The cell wall picks up the blue-green dye, masking the normal phenotype of these cells. But you can see the true branching.

14. When moss chloronemata run into bad conditions, bulbils can be produced to endure the climate until better conditions return.

15. In good conditions, the moss chloronema can produce parenchyma that organizes into a “shoot” with “leaves.” You should notice the spiral phyllotaxy.

16. A longitudinal section of a moss “stem” (axis) shows cortex cells at the far left-edge.
Cells with red walls and simple pits are called hydroids. The red-staining material is not lignin, so these cells cannot be called xylem.
Cells with blue walls and blue cytoplasm conducting photosynthate through the plant are called leptoids.
Are mosses vascular?
Ross: YES THEY ARE!

17. Polytrichum stem cross section
Epidermis
Cortex
Hydroids
Leptoids

18. Moss gametophyte axes has spirally-arranged phyllids

19. The moss phyllid has a midrib, and expanded blade, and margins

20. http://en. wikipedia. org/wiki/File:Plagiomnium_affine_laminazellen

21. photosynthetic filaments
Moss leaves have differing leaf anatomy
Mnium
mesophyll
photosynthetic sheet
leptoids
hydroids
Polytrichum
cutinized terminal cells
photosynthetic filaments
cutinized lower epidermis
mesophyll

22. The terminal cell has a wall with?
The photosynthetic layer is filamentous. like?

23. The first drop fills the cup.
Polytrichum: male gametophytes have a splash cup of leaves containing antheridia that produce sperm
The first drop fills the cup.
Water causes the sperm to shed into that first drop.
Subsequent drops cause the sperm-water to splash out.

24. Longitudinal section through splash cup reveals many antheridia
all tissues here are haploid!

25. antheridium sterile jacket
spermatogentic tissue
stalk
sperm

26. Bryophyte spermatozoid
Sketch by K. Renzaglia

27. The terminal phyllid tufts include the archegonia.
Polytrichum female gametophytes lack the splash cup
The terminal phyllid tufts include the archegonia.

28. cap cell
neck
open neck
archegonium
neck canal cells
immature archegonium
ventral canal cell
zygote
venter
young sporophyte
egg
stalk

29. The moss sporophyte develops at expense of the gametophyte
haploid archegonium neck and venter tissue (calyptra)
elongating diploid sporophyte tissue
photosynthetic haploid phyllid tissue

30. Developing sporophytes show at least some green color.
haploid calyptra shrouds the diploid capsule (sporangium) within
diploid seta
haploid phyllids shroud the embedded diploid foot
haploid gametophytes

31. “Exploded” view of Polytrichum sporophyte and gametophyte
calyptra
cross-section of diploid seta
cutinized epidermis
capsule
cortex
seta
leptoids
hydroids
foot
gametophyte

32. Polytrichum capsule (sporangium) longisection
All these diploid sporophyte cells initially surrounded diploid sporocytes.
The sporocytes were diploid cells that underwent meiosis.
Each sporocyte produced four haploid cells that develop desiccation resistant walls to become spores
diaphragm
peristome teeth
columella
haploid spores
sterile jacket
seta attachment

33. When the calyptra and cap desiccate and abscise the operculum is exposed.
The peristome teeth are revealed.
The peristome teeth respond to humidity to shed spores only in dry air for dispersal

34. The peristome teeth can be used to help identify moss species
Genus Tetraphis
Genus Tortula

35. Funaria peristome teeth are attached to a small diaphragm and twist like Venetian blinds to release spores
Atrichum peristome teeth are attached to a wide diaphragm and lift the diaphram in dry air to release spores.

36.
Orthrotrichum patens

37. The sterile jacket shrinks downward revealing the columella.
The peristome teeth reflex like the petals of a flower and are colorful.
The sterile jacket shrinks downward revealing the columella.
The spores are brightly colored and sticky (insect dispersed).
Splachnum is a dung moss
Splachnaceae Moss
Apophysis Color
Dung Collected
Haplodon wormskjolffi
Brown purple
Human, lemming
Splachum ampullaceum
Light Purple
Reindeer, moose, cattle, sheep
Splachnum luteum
Yellow
Reindeer, moose
Splachnum rubrum
Dark red
Splachnum ovatum
Dark purple
Cattle
Splachnum vasculosum
Sheep, reindeer
Tayloria longicollis
Brownish green
Human
Tetraplodon ongustatus
Light brown
Carnivores
Tetraplodon mnioides
Purplish black
Sheep, reindeer, yak
Data from Bequaert (1921), Crum (1972), Iwatsuki & Steere (1975), Koponen & Koponen (1978), Nyholm (1954), Steere (1973), Watson (1955).

38. Splachnum rubrum/luteum growing on moose dung

39. Tetraplodon mnioides growing on moose dung

40. Tayloria mirabilis growing on cattle dung

41. The phyllid color difference here has to do with water in empty cells rather than air refracting light.
unshed
Sphagnum moss sporophytes (shown attached to gametophytes) explode to blast their spores into the air.
shed

42. Longitudinal section of a Sphagnum sporophyte
pressure-containing sterile jacket
spores
pressure chamber has air for driving spores
seta
drying out

43. Sphagnum moss gametophytes with attached sporophytes
unshed
shed

44. Physcomitrium capsules open into a cup-like form
The pyriform (pear-shaped) capsule opens.
The peristome flares out to form a funnel-like opening
Air moving across the peristome lifts dry spores into the air for dispersal.
This is a Bernouilli effect.

45. When is a “moss” not a moss?
These hanging plants are often called “Spanish moss.”
The plant is not a bryophyte.
It produces small flowers and small fruits.
The plant is a relative of pineapple and bromeliads.
Tillandsia usneoides is the name of this flowering plant.