Citations:iris

plural iris

 * 1989, Ann Lovejoy, The Year in Bloom
 * Is there anything more spectacular than the bearded iris in their short season?
 * 1996, Katherine Grace Endicott, Northern California Gardening
 * Tall bearded iris are in bloom now.
 * 2004, Diana Beresford-Kroeger, A Garden for Life
 * The bulbous iris are important because their early flowers provide a food source for bees and early flying insects.

plural irides

 * 1843, The Penny Cyclopaedia of the Society for the Diffusion of Useful Knowledge
 * In colour the irides are straw-yellow, the pupils black; forehead, nape, and back, very dark bluish-black; [...]
 * 1989, Robert S Ridgely, The Birds of South America
 * As in the caciques, bills are sharply pointed and pale, while irides are usually pale blue.
 * 2001, John V Forrester et al., The Eye
 * Later in life brown irides are the result of heavily pigmented melanocytes within the stroma.

plural irises

 * 1987, Pamela Harper, Frederick McGourty, Perennials
 * Tall bearded irises are easy to grow but not always easy to grow well.
 * 2000, Kevin C Voughn, Louisiana Iris
 * Most iris lovers feel that Louisiana irises are now large enough.
 * 2002, John E Bryan, Bulbs
 * All these irises are sold as dry, dormant bulbs in fall.