2. Rhizoid Colony Formation

3. Bacillus subtilis.  These gram positive, sporeforming rods produce colonies which are dry, flat, and irregular, with lobate margins.

4. Pseudomonas aeruginosa
Pseudomonas aeruginosa.  This gram negative rod forms mucoid colonies with umbonate elevation.  Some strains produce a diffusable green pigment and a distinctive fruity odor.  P. aeruginosa is an opportunistic contaminant of burn injurys, wounds such as cuts and gunshot, and can cause bacterial pneumonia.  It is often nosocomial pathogen, easily transmitted by hands and invasive medical procedures.

5. Salmonella choleraesuis serovar typhimurium
Salmonella choleraesuis serovar typhimurium.  This gram negative rod is a component of the gastrointestinal tract of birds and reptiles and is an agent of gastroenteritis in humans.  It forms shiny, convex colonies with entire margins.

6. Escherichia coli.  This gram negative rod (coccobacillus) forms shiny, mucoid colonies which have entire margins and are slightly raised.  Older colonies often have a darker center.

7. Rhodospirillum rubrum
Rhodospirillum rubrum.  Pinpoint circular colonies which are convex with entire margins.  This gram negative spirillum produces a non-diffusable red pigment.

8. Micrococcus luteus.  Circular, pinhead colonies which are convex with entire margins.  This gram positive coccus produces a bright yellow, non-diffusable pigment

9. Staphylococcus aureus
Staphylococcus aureus.  Circular, pinhead colonies which are convex with entire margins. This gram positive coccus often produces colonies which have a golden-brown color.

10. Staphylococcus epidermidis
Staphylococcus epidermidis.  Circular, pinhead colonies which are convex with entire margins.  The colonies of this gram-positive coccus appear either the color of the agar, or whitish.

11. Lenticular cloud

12. Lenticular Cloud over Mt. Shasta

13. Lenticular: Shaped like a double convex lens
Lenticular: Shaped like a double convex lens. Lenticular sproangia of Physarum viride

14. Umbonate

15. Colony Edge patterns

16. Pellicle floating on broth

17. Paramecium feeding on flocculent bacterial mass.

18. Filamentous Bacteria in a Hot Spring

19. The End