The principal fabric from which Starfleet uniforms are made in the late 23rd century, xenylon is synthesized from algae. When spiroid energy waves in the Cepheus system caused all organic matter aboard the U.S.S. Enterprise to begin shrinking on stardate 5577.3 (2269), the algae-based synthetic fibers in the crew's uniforms shrank along with the crewmembers inside them.