Iostephane is a genus of Mexican flowering plants in the family Asteraceae.Bentham, George. 1873. Genera Plantarum 2: 368 in LatinStrother, J. L. 1983. Pionocarpus becomes Iostephane (Compositae: Heliantheae): a synopsis. Madroño 30: 34-48.Tropicos, Iostephane Benth. They were first published in G.Bentham & J.D.Hooker, Genera Plantarum Vol.2 on page 368 in 1873.
The species are rosette-forming herbaceous perennials that produce relatively large heads with yellow or purple (I. heterophylla) rays. They have large, somewhat quadrate cypselae (achenes), that may either have or lack a pappus.
Molecular phylogenetic studies by Schilling in 1991,Schilling, E. E. and J. L. Panero. 1991. Evidence for a close relationship between Iostephane and Viguiera sect. Maculatae (Asteraceae: Heliantheae). American Journal of Botany 78: 1054-1062. suggested that there is an unexpectedly close relationship between Iostephane and Dendroviguiera (formerly Viguiera sect. Maculatae), a genus of shrubs and trees that is also endemic to Mexico.Schilling, E, E. and J. L. Panero 2011. A revised classification of subtribe Helianthinae (Asteraceae: Heliantheae). II. Derived lineages. Botanical Journal of the Linnean Society 167: 311-331.
Species As accepted by Plants of the World Online, and Global Compositae Checklist; Iostephane heterophylla (Cav.) Benth. – widespread from Chihuahua to Oaxaca Iostephane madrensis (S.Wats.) Strother – Chihuahua Iostephane papposa J. J. Fay – Oaxaca Iostephane trilobata Hemsl. – Chiapas, Oaxaca, Puebla, México State
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