Agostina B. Sassone

Multivariate studies of Ipheion (Amaryllidaceae, Allioideae) and related genera

Ipheion, as recognized by Guaglianone (Darwiniana 17:159–242, 1972), is a small genus of the family Amaryllidaceae, subfamily Allioideae, tribe Gilliesieae endemic to South America. Since 1800, the species of Ipheion were treated under Beauverdia, Brodiaea, Milla, Nothoscordum, Tristagma or Triteleia. Nowadays, some species of Ipheion are treated as Tristagma and some other under Nothoscordum. In this paper, we analyzed the morphological variation among species of Ipheion and related genera using a numerical taxonomic approach based on overall similarity, to investigate the intergeneric and infrageneric variations to the circumscribed groups. Based on 141 operational taxonomic units and 51 morphological characters, multivariate analyses were performed. Results showed that Ipheion separated into two groups according to Guaglianone’s sectional treatment: Ipheion sect. Ipheion is morphologically more similar to the studied species of Tristagma, while I. sect. Hirtellum can be separated from Nothoscordum/Zoellnerallium and from Tristagma and allies. These a priori groupings were tested using discriminant and univariate analyses. Diagnostic characters were selected to differentiate groups. Previous taxonomic treatments are discussed and results are also evaluated using additional karyological and geographical data.

Beauverdia, a Resurrected Genus of Amaryllidaceae (Allioideae, Gilliesieae)

Abstract Based on morphological evidence, we resurrect the genus Beauverdia to include species of Ipheion section Hirtellum. All species now included in Beauverdia were also treated as part of Ipheion, Nothoscordum, or Tristagma. As here circumscribed, Beauverdia (Amaryllidaceae, Allioideae, Gilliesieae) is a South American genus that is found in Argentina, southern Brazil, and Uruguay. Two new combinations, Beauverdia dyalistemon (Guagl.) Sassone & Guagl., comb. nov. and Beaverdia hirtella var. lorentzii (Herter) Sassone & Guagl., comb. nov. are made, as well as descriptions, keys to related genera and species, lectotypes, and distribution maps.

Reconstructing the phylogenetic history of the tribe Leucocoryneae (Allioideae): Reticulate evolution and diversification in South America

At present, the Allioideae is included within the Amaryllidaceae, which is an economically important bulb crop subfamily that includes onion, garlic, and ornamental species worldwide. The Allioideae includes four tribes geographically disjunct namely: Allieae, widespread in the northern hemisphere, tribe Tulbaghieae distributed in South Africa, and tribes Leucocoryneae and Gilliesieae are endemic to South America. Although we agree with the current tribal circumscription of the Leucocoryneae including Beauverdia, Ipheion, Latace, Leucocoryne, Nothoscordum, and Tristagma, there are still taxonomic and phylogenetic uncertainties regarding the monophyly, phylogenetic relationships, and divergence time of several lineages in a biogeographic context. In this study, a comprehensive molecular phylogeny of the tribe Leucocoryneae was inferred based on nuclear ribosomal ITS and plastid (ndhF and matK) sequences. We used Bayesian inference and maximum parsimony analyses to predict ancestor-descendant relationships. Our results confirmed the monophyly of the four tribes of subfamily Allioideae. Similarly, within the Leucocoryneae, Ipheion, Leucocoryne, and Nothosocordum Sect. Inodorum were also monophyletic; Tristagma and Nothoscordum would be monophyletic if including Ipheion and Beauverdia, respectively. Network analyses were implemented to reveal putative scenarios of reticulate evolution. Both, current and ancestral hybridization events have presumably occurred among species of Nothoscordum Sect. Nothoscordum and Beauverdia favored by spatial overlapping of populations, flowering synchrony and a puzzling pattern of cytogenetic attributes. The estimation of divergence time indicates that the tribe Leucocoryneae originated in the Late Oligocene in southern South America with possible ancestors in Africa. Most crown lineages within the tribe diversified in conjunction with biogeographical events during the Late Miocene to Pliocene. We posit that new suitable environments available after the Andean uplift and during the Age of the Southern Plains provided the favorable geographic setting for the major lineages of Leucocoryneae in southern Pampas, extra-Andean Patagonia, Andean mountains, and in Chile. Hybridization, polyploidization, and Robertsonian translocations of chromosomes have been the driving forces and major sources of speciation in the evolution of tribe Leucocoryneae.

Revisión Taxonómica de las Especies del Género Sudamericano Tristagma (Amaryllidaceae, Allioideae)

Resumen Tristagma Poepp. (Amaryllidaceae, Allioideae) se caracteriza morfológicamente por la combinación de una espata compuesta por dos brcteas connadas en la base, un tubo floral que siempre cubre al ovario y filamentos estaminales dispuestos en dos series. Tanto la circunscripción genérica, como la de las especies de Tristagma ha sido fuente de confusión, principalmente debido a la dificultad de encontrar ejemplares de herbario completos, la floración temprana, la abundancia de taxones descritos o transferidos a Tristagma y la falta de una clave para las especies. Sobre la base de una exhaustiva revisión bibliogrfica y estudios morfológicos, se presenta una breve historia taxonómica del género, una descripción del mismo y se reconocen 12 especies, incluyendo su distribución geográfica, fenología, nuevas ilustraciones y una clave para las especies. Nuestra revisión incluye el estudio de ca. de 500 especímenes, la visita a 42 herbarios y la designación de un neotipo.

Lectotypification and Correct Author Citation of Ipheion uniflorum (Amaryllidaceae), with a New Synonym

The type of the generic name Ipheion Rafinesque is Milla uniflora Graham but the same specific epithet had been used in Triteleia by Lindley a few years earlier for the same species with a different type. Confusion ensued concerning the correct author citation for the species under Ipheion. A taxonomic history of the name Ipheion uniflorum (Graham) Raf., a new synonym for this species, and a lectotype for Milla uniflora are presented herein.