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Biology LibreTexts

Seedless Plants

Seedless Plants (Kingdom: Plantae)

Bryophytes

The following sections in the class lecture notes on seedless plants will be helpful as you do this laboratory exercise:

Phylum: Bryophyta (Mosses)

Moss growing on a rock.

1. Observe different kinds of moss on display and note the body form of the gametopyyte.

2. Obtain live sporulating moss and identify the sporophyte and gametophyte generations.

Moss gametophytes and sporophytes
(Click on the photograph.)

3. Draw the life cycle of a typical bryophyte such as moss. Your drawing should contain the following terms:

  • 2N, N, sporophyte, sporangium, meiosis, spores, protonema, gametophyte, antheridium, sperm, archegonium, egg, fertilization

4. Observe a slide showing the antheridial head of Mnium (a moss). Begin using the scanning (4X) objective and then switch to the low power objective (10X). 

5. What is produced in this structure (the antheridium)?

6. Show where the antheridium occurs on the live moss plant. Indicate where this structure occurs in the life cycle diagram that you prepared (above). 

Mnium (a moss) antheridial head
Mnium (a moss) antheridial head x40
Mnium (a moss) antheridial aead x100

7. Observe a slide showing the archegonial head of Mnium (a moss). Begin using the scanning (4X) objective and then switch to the low power objective (10X). 

8. What is produced in this structure?

9. Show where the archegonium occurs on the live moss plant. Indicate where this structure occurs in the life cycle diagram that you prepared (above). 

Moss archegonial head x40
Moss archegonial head x100

10. After the egg is fertilized, it grows and produces a sporophyte. A capsule containing a sporangium is found at the tip of the mature sporophyte. Click on the photograph below to view a sporophyte.

11.Use a dissecting microscope to view a longitudinal section (cut lengthwise).

12. What is produced within this structure (the capsule)?

13. Be sure that you can identify the sporophyte and the sporangium on the live moss plant. Indicate where these structures occur in the life cycle diagram that you prepared (above). 

Moss capsule containing spores    
Moss capsule x40

14. How are moss spores dispersed to new locations?

Phylum: Hepatophyta (Liverworts)

1. Observe live Marchantia (a liverwort).  Do the plants contain gemma cups? What is the function of gemma cups?

Marchantia (live)

Seedless Vascular Plants

Phylum: Pterophyta

Ferns
Fern gametophyte

1. Draw the life cycle of a fern. Your drawing should contain the following terms:

  • 2N, N, sporophyte, sorus, sporangium, meiosis, spores, gametophyte, antheridium, sperm, archegonium, egg, fertilization

2. Observe sori on the underside of a fern leaf. Are sporangia visible? Indicate where this structure occurs in the life cycle diagram that you prepared (above). 

Fern showing sori on
underside of leaf
Fern sorus x40
Enlarge the image to v iew the sporangia.

3. View a slide of a fern gametophyte showing antheridia. What reproductive cells are produced by gametophytes? Indicate where the gametophyte occurs in the life cycle diagram that you prepared.  

Fern prothallium (gametophyte)
showing archegonia x40
Horsetails
Horsetails

1. Observe a live horsetail if available. Find the a strobilus. What reproductive structures are contained within the strobilus?

Horsetail showing strobilus

Phylum: Lycophyta

Members of this phylum have horizontal stems, upright stems, and small, spike-shaped leaves called microphylls.

Club Mosses

1. Observe a specimen of live club mosses such as Lycopodium. Find rhizomes. Identify microphylls. Do the specimens have any strobili? (Be sure to look up these words if you do not understand them.)

Club moss (lycopodium
Spike Mosses

1. Observe a specimen of a spike moss such as Selaginella. Note the structure of the microphylls.

Spike moss (selaginella