Cirsium (Thistle) sp. Pollen
                This pollen grain was recovered from an air sample
                  collected in Eastern Washington State during August 2012 at an
                  elevation of 1700 feet.
              
              
                Transmitted Brightfield Illumination
                
Definition/Function:
                Significance in the Environment:
                Characteristic Features:
                Associated Particles:
                References:
                Faegri, Knut and Johs Iversen, TEXTBOOK OF POLLEN ANALYSIS, Hafner Publishing Company,
                1964.
                Kapp, Ronald O., HOW TO KNOW POLLEN AND SPORES, Wm. C. Brown Company, 1969.
                Moore, P.D., J. A. Webb, and M. E. Collinson, POLLEN ANALYSIS, Blackwell Scientific
                Publications, 1991