On the other hand, standard, or open pollinated varieties are more or less stabilized in their characteristics. They remain fairly consistent, producing seed that will grow into plants more or less like their parent plants, though less uniform than hybrids.
The rank of admiral (or full admiral, or four-star admiral) is the highest rank normally achievable in the U.S. Navy. It ranks above vice admiral (three-star admiral) and below fleet admiral (five-star admiral). There have been 262 four-star admirals in the history of the U.S. Navy. Of these, 221 achieved that rank while on active duty, 40 were promoted upon retirement in recognition of combat citations, and one was promoted posthumously.
For the army, navy, and air force, no more than about 25% of the service's active duty general or flag officers may have more than two stars, and statute sets the total number of four-star officers allowed in each service. This is set at 6 four-star navy admirals. Some of these slots are reserved by statute.