Who knew you needed a college degree to select the ideal sheets for your meticulously decorated bedrooms? From sateen to percale to fleece to flannel -- nevermind the thorny issue of thread counts -- bedding and towel purchases go better with a cheat sheet to clarify choices. Supima and Egyptian cottons are high-end home linens options that are worth understanding. You get what you pay for -- but only after you understand what the labels mean.

Supima, Homegrown Luxury

American cotton growers weren't content with the limited crops of high-grade, long-fiber Sea Island cotton that could be produced off the Georgia coast. They experimented with an ELS -- extra-long staple -- fiber grown in Peru to find a cotton that could rival premium Egyptian cotton and grow to a reliable standard. Pima cotton is a very long fiber that is strong, soft, non-pilling and very durable. The name comes from the Pima Indians who cultivated the cotton in Arizona as American producers searched for a superior blend. Supima is the result of that research. The name means simply "superior Pima cotton" and is trademarked and strictly regulated. The threads are uniformly extra-long, and the cotton has all the virtues of Egyptian cotton with fewer uncertainties. Supima is a luxury product with the longest fibers, softest feel, excellent dye absorption and bright colors, and durability.

Egyptian, Export From the Nile

The standard for luxury linens was set by the ELS fibers of a soft but sturdy cotton grown on the banks of the Nile. Egyptian cotton was the benchmark against which other, shorter fiber cottons were measured. The staple is long, and the material is long-lasting, a smooth cotton that high-end manufacturers and retailers reserved for customers who could afford the best. And, for a long time, Egyptian cotton was the best. Sheets and towels made from Egyptian cotton are still a good investment, as well as an indulgence. But the "brand" is not as strictly regulated as Supima, and some shorter staple Egyptian cotton does find its way to market. Luxury ELS Egyptian cotton products usually carry a tag with a white cotton boll on a black triangle and the words Egyptian Cotton. Genuine Egyptian cotton or Supima sheets and towels are plush and practical additions to your linen closet.