Iris Neoplasms: Tumors of the iris characterized by increased pigmentation of melanocytes. Iris nevi are composed of proliferated melanocytes and are associated with neurofibromatosis and malignant melanoma of the choroid and ciliary body. Malignant melanoma of the iris often originates from preexisting nevi.Iris: The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.Iris Diseases: Diseases, dysfunctions, or disorders of or located in the iris.Iris Plant: A plant genus of the family IRIDACEAE that contains IRIP, a type-1 ribosome-inactivating protein, and iridals (TRITERPENES).