Tristagma is a mostly South American genus in the Alliaceae family that is related to Nothoscordum and Ipheion. The taxonomy of this genus is in question. This genus has leaves that are usually linear and flat, rarely canaliculate, terete of filiform. Many of the species are from Chile and Argentina and are alpine plants. In 1963 Hamilton P. Traub proposed moving Ipheion to Tristagma. Although not everyone is in agreement, this seems to be widely accepted at the moment. The plants previously included in Ipheion are mostly from Argentina and Uruguay but with one flowered inflorescences unlike some of the original species in this genus which are multi-flowered. They have leaves that smell like onions when crushed. Although they are dormant in summer in the wild, many of them grow in areas with year round rainfall and may benefit from some summer moisture. The species most often grown is Tristagma uniflorum (syn. Ipheion uniflorum) from Argentina. There are many selections of this species and you will see it listed on the web both ways. Until there is more study of all these plants, we are placing them on the wiki page with the names that our South American members Alberto Castillo and Germán Roitman suggest. Many of the yellow flowered species that are still considered Ipheion species by some who do not agree with Traub can be found on our Nothoscordum wiki page.
Tristagma bivalve (Lindl.) Traub syns. Ipheion bivale (Lindl.) Traub grows in the mountains above Santiago, Chile. It can be grown like a Cape bulb or better as a Texan Cooperia. T. bivalve looks like a several flowered medium sized Ipheion uniflorum. This species is not to be confused with Nothoscordum bivalve which is an entirely different plant that has a tall scape with minute flowers. Photo by Osmani Baullosa.
Tristagma hirtellum (Kunth) Traub, see Nothoscordum hirtellum
Tristagma 'Jessie' is a seedling of 'Rolf Fiedler' obtained by Tony Hall of Kew and named for his late sister, Jessie. 'Jessie' has the deepest blue flowers. Jane McGary writes 'Jessie' is indeed a remarkable color, a real gentian blue, very like the color of Commelina dianthifolia. Photo 1 of the flower was taken by Mary Sue Ittner. Photos 2 through 6 from M. Gastil-Buhl show the bulbs on a 1 cm grid, the color compared to blue painters tape, the underside tepal markings and blooms in March 2012. The bulbs multiply with up to a dozen offsets attached as shown in photo 6 on a 1 cm grid.
Tristagma recurvifolium (C.H.Wright) Traub is from Uruguay. It was originally named in 1915 by C.H. Wright as Brodiaea recurvifolia. It is listed as a synonym in the Kew checklist for Tristagma sessile (Phil.) Traub. See below for notes on that species for the confusion of what name to use for the photos below. Whatever the correct name should be, this species has white flowers and blooms in early winter, increasing well by offsets. Photos by John Lonsdale of plants originally known as Ipheion sessile.
Tristagma 'Rolf Fiedler' This is an unnamed species. It is a narrow endemic from Uruguay. So far it has been found on two hill tops after many years of being a plant of unknown origin. As those who have grown this and Tristagma uniflorum have found them to be very different. Moreover, they grow in the same region of Uruguay and over there they look different. This plant has bright blue flowers. This is another plant in this complex that is controversial. Some feel Rolf Fiedler is really Tristagma peregrinans P. Ravenna but this plant has not been verified by anyone except for the person who named it. It has not been found and the drawing submitted with the naming of this plant shows bulbs that look very different than the plant in cultivation. Photos by Sheila Burrow, Jay Yourch, John Lonsdale and David Pilling. Photo 5 shows bulbils appearing at the end of the growing season and photo 6 seed.
Tristagma sellowianum (Kunth) Traub, see Nothoscordum felipponei
Tristagma sessile (Phil.) Traub is listed in Kew as the accepted name for Ipheion sessile. But our South American authority says the correct name for what has been known as Ipheion sessile in the past should be Tristagma recurvifolium. IPNI lists this species as originally named by Philippi in 1858 (as Triteleia sessilis) who named plants from Chile. When Traub renamed it to Ipheion sessile (Phil.) Traub in 1953 and then to Tristagma sessile (Phil.) Traub in 1963 he was clearly using a record of a plant from Chile. The data bases that now list Tristagma sessile as the correct name list it as a species native to Uruguay. It's all very confusing.
Tristagma sp. is an alpine species from Chile different from T. bivalve. It has scentless flowers that are shaped like a narrow cup facing up. Photo by Osmani Baullosa.
Tristagma uniflorum (Lindl.) Traub, syn. Ipheion uniflorum, is still known by many under the synonym. It is native to Argentina and Uruguay. It has starry flowers and blooms over a long period in spring. This plant has naturalized in many parts of the world. Photos 1-2 taken by Mary Sue Ittner of plants growing in her garden. Photos 4-5 taken by Travis Owen show a form sold as "Ipheion uniflorum" with dark purple midveins. Photo 4 shows the flower closed at night. Photo 5 of seed by David Pilling.
Tristagma uniflorum 'Charlotte Bishop' is a form with large pink flowers.
Tristagma uniflorum 'Froyle Mill' is a selection with purple flowers. The first two photos by Mark Mazer.
Tristagma vittatum (Griseb.) Traub, see Nothoscordum vittatum