Answer:
White primaries were primary elections held in the Southern United States in which only white voters were permitted to participate. ... The Texas Legislature passed a law in 1923 that allowed political parties to make their own rules for their primaries.
The first stanza of the poem shows this explicitly where they say that there's an old lady on an island that has a daughter who lives on a different continent with an ocean in between. This is easily seen in the first four lines of the poem.
Saturn's rings are thought to be pieces of comets, asteroids, or shattered moons that broke up before they reached the planet, torn apart by Saturn's powerful gravity. They are made of billions of small chunks of ice and rock coated with other materials such as dust. The ring particles mostly range from tiny, dust-sized icy grains to chunks as big as a house. A few particles are as large as mountains. The rings would look mostly white if you looked at them from the cloud tops of Saturn, and interestingly, each ring orbits at a different speed around the planet.
They came to Jamestown to start a colony for England, search for gold, and escape religious persecution.