Lab 4: Cyanobacteria, Algae, and Byrophytes (Mosses)


  1. Expedition and collection
  2. Examination and sketching
  3. Scanning


During the expedition phase wait to begin collecting samples until we are at the collecting site below the dormitories. Collect algaes and mosses. On the way back one group should obtain a sample of green material in the false staghorn fern field puddle. Each group should also collect a sample of the green jelly like material in front of the faculty building (available elsewhere upon inspection).


Upon return to the laboratory, assist in the set-up of microscopes. We will attempt to set up six compound microscopes and a single dissecting microscope.

Set up the green jelly like sample first on a compound microscope and attempt to identify the substance. Remember to start at low magnification and to carefully move to higher magnifications. Each member of the group should sketch the substance. Note whether it is motile or non-motile and any special features it has. Your instructor will cover some of the features you might see in class. If you get a chance, look at some of the other groups samples. The microscopes are of varying capabilities and some may provide an enhanced image.

Follow this set up with an algae set up. If your algae is not already in water, you should create a suspension of the algal material and water. Observe carefully your preparation. There may be present both Cyanobacteria (prokaryotic blue-green algae) and eukaryotic green algaes. The later will be most easily distinguished if there are clear chloroplast structures. Experience to date suggests that cyanobacteria will outnumber any eukaryotic algaes. Look carefully and have a look at what your neighbors have found. Sketch the various chlorophyll containing organisms you see. Include information on motility (do they move? how?) and whether or not you see any signs of cilia. Include cell walls and any internal structure that you can see.

Finally set up a moss and examine a moss under the microscope. You will probably have to use a single edge razor to carefully separate a few blades from the moss to get the best view. Again, move around the lab and see what other groups have found. The different microscopes may have differing resolutions. Produce three sketches of the moss:

  1. The macroscopic overall morphology of the moss, a sketch of the moss plant itself.
  2. Sketch the pattern of cells in a single moss blade, leaving out the details seen inside each cell.
  3. Sketch a single cell including features seen inside the cell

When done: clean up and help with putting away the microscopes!


Take the moss to the computer laboratory and scan it with the scanner. Adjust the magnification to produce an image 200 pixels wide. Save it in a web page on your disk as a JPEG at 95% quality. Turn in your disk with your sketches to complete the laboratory!



The jelly like substance has been tentatively identified as a cyanobacteria, possibly a Nostoc or an Anabaena. Another cyanobacteria, of the Oscillatoria, has been seen in stagnant pools of rainwater. The algaes are presently unidentified as are the mosses.

Instructor: Dana Lee Ling

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