Lab #3 Class Bryopsida

Home , Mnium, Plagiomnium, Plagiomnium insigne, Rhizomnium, Rhizomnium glabrescens, Rhytidiadelphus

By the end of the term you are required to know a number of bryophytes by sight. Organisms presented in lab as part of the exercises and as special features (the Bryo du Jour), as well as common bryophytes we find on fieldtrips will also be fair game. You will get plenty of practice playing the “Name that Bryo” game. As the term progresses images of habitat, habit, and structure will be added to the Public Biology 321 website/blog. As we work through the bryological material we will also identify interactions with other organisms. There are many protists, fungi, and insects that make bryophytes their home! Use the Appendix, page v to record your observations.

Class Bryopsida http://blogs.ubc.ca/biology321/?page_id=70

Terms to Know: antheridium archegonium attenuate cordate decurrent diplolepideous endostome exostome haplolepidous lamina multiseriate multistratose neck

20 neck canal papilla paraphyllia paraphyses perigonium pinnate pleurocarpous protonema squarrose uniseriate unistratose venter

LAB #3A CLASS BRYOPSIDA

1. Protonema

Examine the demonstration sample of protonema on soil. It forms a tight green mat. The protonema in the Petri dish was grown from spores in culture (similar to what you did in last day’s lab). Take a sample from the Petri dish and make a slide. Refer to your “Microscope Use” hand-out to set up your compound microscope in Kohler (instructors will help if you have never done this). Examine the protonema. Refer to your lecture notes and describe/draw the general structure.

Explain the benefit to having an extensive protonematal stage?

When would it not be advantageous?

2. Plagiomnium insigne http://blogs.ubc.ca/biology321/?page_id=516

(Fig. 3-2, Schofield pages 210-211)

On our fieldtrip we found this moss growing in a lawn under street trees. You will also find it in Pacific Spirit and Stanley Park along shaded trails and at the base of big-leaf maples (Acer macrophyllum)

Gametophyte Structure Examine the gametophyte. Note the spiral arrangement of the leaves and the distribution of rhizoids. Remove some rhizoids and make a slide. How do they compare with the rhizoids you observed in Dicranum scoparium in Lab 1? If your diagram from the first lab is difficult to interpret you should draw the rhizoids of Plagiomnium and indicate the oblique (diagonal) cross walls.

Remove leaves from a shoot and make a cross-section through the stem. Examine it with the compound microscope. Make a sketch of the section and label. Is there a conducting strand?

Plagiomnium insigne has very large leaves. They are decurrent (the leaf base extends down the stem below where the middle part of the leaf is attached). Make a wet mount of a leaf and examine it with the dissection microscope. Describe the main features of the leaf.

22 Examine the leaf with the compound microscope. Draw a tooth to show the arrangement of cells within the structure, the leaf margin, and the cells of the blade.

Make a cross-section through the leaf. Note that the blade (lamina) is unistratose, Which part is multistratose?

Examine a portion of the section through the costa. There is remarkable differentiation of cells in the costa, including stereids (thick-walled, elongate fiber-like cells) and a central strand of conducting cells. Draw a portion of the leaf section through the costa. Label.

Archegonial Plants: Note the plants with immature sporophytes. The seta elongates prior to sporangial development. The calyptra is like a little hat on the tip of the sporophyte. Explain the origin of calyptrae. What ploidy are they?

23 Antheridia Plants: Note the plants with splash cup perigonia that contain paraphyses and antheridia.

Place a drop of water on a microscope slide on the stage of the dissecting microscope. Tease out the contents of the perigonium into the water. Spread the material apart and add a cover slip. Examine with the dissecting microscope. Note the uniseriate paraphyses and the sac-like antheridia. Sketch.

Examine the prepared slide of a longitudinal section of “Mnium” through the perigonium. Identify the antheridia and paraphyses. Note that there is no evidence of an apical cell; it has been “used up” during differentiation of the perigonium.

Label Fig. 3-2 with as many structures as you can. Include ploidy for all labeled structures. 24

Fig. 3-2 Plagiomnium insigne

3. Rhizomnium glabrescens (Fig. 3-3) http://blogs.ubc.ca/biology321/?page_id=514

Archegonial Plants: Like its name indicates this moss has lots of rhizoids! In Pacific Spirit Park we found it on the bark of an overturned tree. You will also find it on rotting wood, soil and rocks in shady woodlands.

This acrocarpous moss has a nodding sporangium. A calyptra should be present on most sporangia. Rhizoids are at the stem base and the leaves are elliptic. Label Fig 3-3 to indicate the components of the gametophyte and sporophyte.

25 Remove a few leaves and examine microscopically (wet mount and cross- sections). Compare the leaf structure of Rhizomnium with Plagiomnium.

Examine the female plants. Pull a sporophyte from a gametophyte; archegonia and paraphyses (sterile, uniseriate structures) should remain attached near the foot (which often remains attached to the sporophyte). Find at least one archegonium with the dissecting scope and then inspect it more closely with the compound scope. Sketch.

Pull off the calyptra (if present) and identify the parts of the sporophyte. Examine the prepared slide of the longitudinal section through the sporangium of “Mnium”. Note the columella. What is its function? Sketch and label with the following terms:.columella, operculum, peristome teeth, seta, sporangial jacket, sporangium.

Antheridial Plant: The antheridial plant is similar to Plagiomnium; the perigonial head consists of flaring rosette of perigonial leaves that resemble petals of a flower, surrounding a dark cluster of paraphyses and antheridia. Explain how sperm is dispersed in these plants.

Fig. 3-3 Rhizomnium glabrescens

If you were walking in the woods and came upon Rhizomnium glabrescens and Plagiomnium insigne, what features would you look for to distinguish between them?

4. Name that Bryo Game / Keying Practice You need to recognize these bryophytes by sight. The list is posted on the website and updated every couple of weeks (Bryos to Know). Do you recognize the bryophytes on display? The names are revealed on the underside of the cards if you don’t know them yet.

For the remainder of this lab try your hand using the key (Schofield’s Key to Some Common Mosses of British Columbia)…..even if you know the identity of the moss you will get practice at using the key. Look at Appendix page v for some amendments to your key. 27

LAB #3B CLASS BRYOPSIDA

4. Claopodium crispifolium (Fig. 3-4) http://blogs.ubc.ca/biology321/?page_id=518

The specimens in lab were collected from the base of a big-leaf maple (Acer macrophyllum). Claopodium crispifolium also occurs on rocks and boulders. Claopodium crispifolium is pleurocarpous, i.e. the sporophytes are on lateral branches that bear perichaetia, while the apex of the shoot exhibits indeterminate growth. Branching is pinnate and in a single plane. Tease out a branch system bearing sporophytes. Calyptrae are present on most sporophytes. Examine the sporophyte with the dissecting microscope. Note that the seta is papillose. The light green branch tips help to identify this species in the field. Remove a few leaves from the stem or branches and place them in a drop of water on a microscope slide. Examine with the compound microscope. Does the leaf have a costa? The leaf is broadly heart-shaped (cordate). The apex has an attenuate point (gradually tapering to a long slender point). Each leaf cell bears a single papilla, best observed in profile on a curved over portion of the leaf, or by focusing up and down to view a shiny dot in the middle of each cell. SKETCH a cell with a papilla.

Fig. 3-4 Claopodium crispifolium

5. (a) Unknown #1 (Key after you have examined the material) These samples were collected from an overturned tree in a coniferous forest. Before you key, take a close look at the sample and identify the main features. Is this moss acrocarpous or pleurocarpous? Describe the leaf arrangement and their orientation relative to the stem.

Examine a leaf with the compound microscope. Is there a costa? Does it have a bordered margin? Is the margin toothed? Are the alar cells different from other cells of the lamina? Draw and label.

Examine the sporophytes. There should be immature as well as mature ones. Draw an immature sporophyte with and without a calyptra.

Examine a dehisced sporangium with the dissecting scope. Draw the sporangium and include the peristome teeth. There are two rows of peristome teeth (endostome=inner row and exostome=outer row of teeth). Make a slide of the peristome teeth and examine the two sets of teeth. Distinguish the endostomal and exostomal teeth.

Key to Species: ___ à ___à ___à ___à ___à ___à ___à ___à ___à ___à ___ à ___à ___à ___à ___à ___à ___à ___à ___à___ à ___à ___à ___à ___à ___à ___à ___à ___à___ à ___à ___à ___à ___à ___à ___à ___à ___à___ à ___à ___à ___à ___à ___à ___à ___à _

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30 5. (b) Unknown #2 (Key after you have examined the material) Observations/Drawings: Describe this moss. Find paraphyllia (filamentous structures between the leaves). What is their function?

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6. Rhytidiadelphus There are three Rhytidiadelphus species common to our area. The genus name reflects its similarity to Rhytidium.

Rhytidiadelphus triquetrus (electrified cat tail moss) http://blogs.ubc.ca/biology321/?page_id=524

This moss can be found in various locations in the lower mainland, most commonly in coniferous forests. It gets its common name from the orientation of the leaves at the branch tips. Remove several leaves of the main stem and examine. Note the longitudinal pleats and double costa (be sure to distinguish the pleats from the costae). The costae extend about 3/4 the length of the leaf. Margins of the leaf bear tiny teeth. Sketch a leaf outline, showing pleats, costae and marginal teeth.

31 The other two members of this genus are more common in our area (you saw them on Fiedltrip #1). Rhytidiadelphus loreus is a woodland species. R. squarrosus is often found in lawns (and considered a weed). Use the glossary in your key to find out what the specific epithet (squarrosus) refers to. Compare and contrast the characteristics of the three species of Rhytidiadelphus. What are key features you would use to identify and distinguish them in the field?

Rhytidiadelphus loreus http://blogs.ubc.ca/biology321/?page_id=526

R. squarrosus http://blogs.ubc.ca/biology321/?page_id=983

7. Key that Moss Observations/Drawings:

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As Time Permits for Practice

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