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Systematics, Phylogeny and Evolution of Dietes (Iridaceae)

1981; Missouri Botanical Garden; Volume: 68; Issue: 1 Linguagem: Inglês

10.2307/2398817

2162-4372

Peter Goldblatt,

Botany, Ecology, and Taxonomy Studies

Dietes is a member of Iridaceae-Iridoideae and is probably the most primitive member Sel Old World tribe Irideae.It shares characteristics of both /ris and the African genus Moraea and is most likely close to the ancestral stock that gave rise to these more specialized genera.Dietes Som USE from the southern Cape to Ethiopia, and three more localized eastern southern African species.Dietes is a small genus of Iridaceae, closely allied to the African genus Moraea and to the widespread Northern Hemisphere genus /ris.Six species are currently recognized, five African and one restricted to Lord Lowe Island in the Tasman Sea between Australia and New Zealand (Fig. 1).In spite of the extraordinary disjunction in the distribution, there seems no doubt that Dietes is a natural genus, all the species sharing unique vegetative and floral structures and a basic chromosome number of x -10. HisTORYThe name Dietes was first proposed by R. A. Salisbury in 1812, but as published it was nomenclaturally invalid, lacking description or reference to a previously published generic description.Salisbury chose the name Dietes to indicate what he believed to be its dual affinities to both /ris and Moraea, a point of view fully supported here.Few authors accepted the genus initially, though Sweet (1830, 1839) put forward several combinations, unfortunately never validating the genus with a description.Dietes appears again in the literature in 1846 in an article by Spae concerning the species currently called D. bicolor.Spae used both Moraea bicolor and Dietes bicolor in the title, but apparently regarded Moraea as the correct generic name.Later, in 1852 when Spae again wrote about D. bicolor, he unambiguously placed it in Moraea.Dietes was only fully accepted in 1866 by Klatt, who provided a complete generic description.Klatt acknowledged Salisbury as the source of the name and recognized three species in the genus, D. bicolor, D. catenulata, and D. compressa.The last two are, in my opinion, the same species and conspecific with the much earlier D. iridioides.It was also Klatt who realized that the newly described Australasian species /ris robinsoniana F. Muell.belonged in Dietes (Klatt, 1882).