The Blue-eyed Grasses, genus Sisyrinchium, are a substantial group of flowering plants of the iris family, Iridaceae. There are between 70 to 150 species (according to different authors), all native to the New World. Several Eastern U. S. species are threatened or endangered.
The taxonomy of this genus is rather perplexing and confusing, as several of these species, such as Sisyrinchium angustifolium, form complexes with many variants named as species. More genetic research and cladistic analysis need to be performed to sort out the relationships between the species. Some species, notably S. douglasii, have been transferred to the separate genus Olsynium.
The name Sisyrinchium is derived from the Greek words sys (pig) and "rhynchos" (nose), referring to the habit of pigs grubbing the roots.
These are not true grasses, but many species are low-growing, and the leaves of some appear to be grass-like; and they do often grow on grasslands. Many species resemble irises, to which they are more closely related. Most species grow as perennial plants, from a rhizome, though some are short-lived (e.g. S. striatum), and some are annuals (e.g. S. iridifolium).
The flowers are relatively simple and often grow in clusters.
Many species, particularly the South American ones, are not blue, despite the common name. Flower colours in the genus includes white, yellow, and purple, as well as blue, often with a contrasting centre. Of the species in the United States, the Western Blue-eyed Grass, Sisyrinchium bellum, is sometimes found with white flowers, while the California Golden-eyed Grass, Sisyrinchium californicum, has yellow flowers.