====== Introduction/General Considerations ====== 

We have compiled a list of 301 distinct phenotypes or unique phenotypic combinations called pages each of which has one or more photo images clearly demonstrate unique characteristics.  These were selected as the best of over 8000 photos taken during the study of our collection of 3484 verified mutants. From these we extracted 828 cases that had striking photos and substantial data for presentation. These mutants were obtained from various mutation trials that include spontaneous mutation, effects of ionizing radiation, ploidy, transposon, and chemical mutagenesis, including ethyl-methane-sulfonate (EMS) and nitrosoguanidine, mostly from my corn projects, but also from projects of Stadler, McClintock, and others.

Each page has a phenotypic name and short definition and each image has a descriptive caption which briefly describes the image and relates it to the definition and to other images on the page.

A phenotype is the observable defined as … (rewrite in own words)
 A particular observable physiological state (Christopher’s definition)
 “the appearance of an organism resulting from the interaction of the genotype and the environment” (from Random House Dictionary).
	

A particular phenotype is a consequence of the mutation of a particular gene to a new form. Things that look like mutant phenotypes but are not inherited are called phenocopies. For example, a disease can cause discoloration of a tissue similar what is also seen from mutations. We made a special effort to include only verified heritable phenotypes, which were obtained as a consequence of mutagenesis.

Phenotypes vary a great deal depending on genetic background, specific genetic modifiers, disease, nutrition, environment, or other non-Mendelian phenomena. Phenotypes can be classified as to what characteristics can be seen in the field or in the laboratory under a microscope, petri dish, or test tube and whether on the kernel, ear, seedling, or the plant.

They could be classified as developmental phenotypes, morphological phenotypes, phenotypes affecting color or distribution of color, phenotypes affecting stature, and/or phenotypes affecting the ear.

Individual mutants often express multiple phenotypes that may or may not be obviously connected, depending on the method of observation and depending on whether the mechanism is understood by the observer.

The photographs were taken by an essentially amateur photographer and under many conditions and have been adjusted by modern technology to approach the quality of what was seen at the time of observation.