Name: ______________________________ Date: ___________________________ BLK: ___________
Moss Lab
PURPOSE
Our objective is to observe the successive stages of the life cycle of a moss and illustrate them in a
diagram.
MATERIALS
Light Microscope
Dissecting microscope
Hand Lens
Petri Dish
Cover slips
Prepared slide of Mnium archegonium, l.s.
Prepared slide of Mnium antheridium, l.s.
Forceps
Slides
water
PROCEDURES
Part 1: Live Moss Sample
1. Observe a sample of moss. Observe the structures with hand lens and dissecting microscopes under low
power.
2. Sketch and label the gametophyte and the sporophyte generation.
3. Use a ruler to measure the size of the gametophyte and sporophyte.
4. Label the rhizoids, sporangia capsule, operculum (capsule lid), and spores.
Part 2: Gametophyte
1. Return to the green leafy gametophyte
2. Remove a small piece of leave and make a wet mounted slide of it.
3. Examine it close up through the high power compound microscope.
4. Draw a close-up of the gametophyte’s cells.
Part 3: Sporophyte
1. If the spore capsule is intact, tease it open by loosening the operculum.
2. Spread the contents out onto a glass slide and prepare a wet mount of the spores.
3. With a high power microscope, observe the spore capsule and the operculum.
4. In your drawing, include a detailed sketch of your observations. Include some spores.
Part 4: Moss Archegonium
1. Obtain a slide of Mnium archegonial head l.s..
2. Examine the slide under LOW POWER. Sketch a diagram of the archegonium and label the
archegonium (which is found inside the surrounding tissue).
3. Record the magnification. Calculate the diameter of the archegonium only.
Part 5: Moss Antheridium
1. Obtain a slide of Mnium antheridia head l.s..
2. Examine the slide under LOW POWER. Sketch a diagram of the whole gametophyte tip structure and
label the antheridium (found inside the surrounding tissue).
3. Record the magnification. Calculate the length of the antheridium only.
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Name: ______________________________ Date: ___________________________ BLK: ___________
OBSERVATIONS
Part A: Live Moss Sample
Total Magnification: ________
Length of one gametophyte strand: ________
Length of one sporophyte strand: ________
Part B: Gametophyte
Part C: Sporophyte
Total Magnification: ___________
Total Magnification: ___________
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Name: ______________________________ Date: ___________________________ BLK: ___________
Part D: Moss Archegonium
Part E: Moss Antheridium
Total Magnification: ________
Calculate the size of the archegonium.
Total Magnification: ________
Total Magnification: ________
Calculate the size of the Archgonium.
Calculate the size of the Antheridium.
Please complete the discussion questions and conclucsion on the back of this page.
DISCUSSION QUESTIONS
1) What are the spores coated with?
2) Why is it important that the spores are coated?
3) Are sporophytes n or 2n?
4) Are the spores n or 2n?
5) Are the gametophyte n or 2n?
6) What is a protonema?
7) What does the protonema become?
8) Is the protonema n or 2n?
9) Is the protonema part of the gametophyte generation or the sporophyte generation?
CONCLUSION
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