Nuevas combinaciones en los géneros sudamericanos Lepidaploa y Lessingianthus (Vernonieae, Asteraceae)

Abstract

Nuevas combinaciones en los géneros sudamericanosque Lessingianthus presenta 120 especies con una gran concentración en el sudeste de Brasil. Se estima que gran cantidad de especies todavía incluidas en Vernonia no han sido estudiadas apropiadamente y en consecuencia su posición y estatus taxonómicos permanecen inciertos. En este trabajo se analizó la morfología de los granos de polen y de algunos microcaracteres florales para aportar datos que permitieron transferir seis taxones de Vernonia al género Lessingianthus y otras dos especies del mismo género a Lepidaploa. PALABRAS CLAVE:Vernonia, Lepidaploinae, Vernoniinae, sistemática. ABSTRACTThe genera Lepidaploa (Cass.) Cass. and Lessingianthus H. Rob. (Vernonieae, Asteraceae) were established to separate taxa initially placed in Vernonia Schreb. sect. Lepidaploa (Cass.) DC. subsect. Axilliflorae Benth. & Hook. and Vernonia sect. Lepidaploa subsect. Macrocephalae Benth. & Hook., respectively. As presently delimited, Lepidaploa is comprised of about 150 species widely distributed in South America, while Lessingianthus presents 120 species having a concentration in southeastern Brazil. It is estimated that a large amount of several species still included in Vernonia have not been examined and consequently their taxonomic position remains uncertain. We analyzed pollen morphology and floral microcharacters of several Vernonia species, which allowed the transfer of six taxa previously placed in this genus to Lessingianthus and other two species of the Vernonia to Lepidaploa.

Male gametophyte development and cytogenetics of natural diploid and polyploid species of the South American genus Lessingianthus (Asteraceae, Vernonieae)

“…Chromosome counts reported for the genus Lessingianthus showed a great variation in the ploidy levels of the species, ranging from diploid (2n = 2x = 32) to 1-decaploid (2n = 11x = 176), and they are all based on the basic chromosome number x = 16 (Angulo & Dematteis, 2012;Pérez et al, 2021). Many species of the genus have high ploidy levels (6x, 8x, 10x) and a taxon with an odd chromosome complement and high ploidy level has also been reported (2n =11x) (Dematteis, 1996(Dematteis, , 1997(Dematteis, , 2002(Dematteis, , 2009Dematteis & Fernández, 2000;Dematteis et al, 2007;Angulo, 2012;Angulo & Dematteis, 2009a, 2009b, 2012. In addition to the large variation in the chromosome number observed, Lessingianthus also shows intraspecific chromosome variation and has species with different ploidy levels, such as L. sellowii (Less.)…”

“…This type of speciation is clear in Lessingianthus if we consider the number of polyploids with high ploidy levels. Despite the large amount of cytological information available for both Lessingianthus and the tribe that confirms the usefulness of chromosomal characters in taxonomic and evolutionary studies (Jones, 1979;Turner et al, 1979;Galiano & Hunziker, 1987;Ruas et al, 1991;Dematteis, 1998Dematteis, , 2002Dematteis & Fernández, 2000;Dematteis et al, 2007;Oliveira et al, 2007aOliveira et al, , 2007bAngulo & Dematteis, 2009a, 2009b, 2012Vía do Pico & Dematteis, 2012, there is little information that contributes to unraveling the mechanisms of origin and establishment of these natural polyploid populations. Establishment refers to the mechanisms underlying the spread or colonization of new populations by neopolyploids (Kreiner et al, 2017).…”

The taxonomic utility of micromorphology in Lepidaploa (Vernonieae: Asteraceae)

“…is one of the genera resurrected from Vernonia sensu lato by Robinson (1990). It comprises 150 species, most of which occur in South America (Angulo et al 2012). In general, Lepidaploa is characterized by sessile heads, nodular style bases, sometimes glandular cypselae, no glands on the anther appendages, elongated raphids on cypselae and pollen of the types C (pollen tricolporate and with polar lacuna), D (pollen triporate and without polar lacuna) and G (pollen tricolporate and without polar lacuna) (Robinson 1990, Keeley and Robinson 2009).…”

A new species of Lepidaploa (Asteraceae: Vernonieae) from Minas Gerais State, Brazil

“…The genus Lepidaploa comprises about 150 species widely distributed in South America (Angulo et al 2012). Lepidaploa is distinguished from the remaining American members of the tribe by the sessile heads, which have 1.3-3 times more involucral bracts than flowers, no glands on the anther appendages, nodular style bases, sometimes glanduliferous cypsela, cypsela wall with prismatic crystals, pollen type C, D or G, and basic chromosome number x= 14, 15 or 16 (Robinson 1990, Keeley & Robinson 2009, Marques & Dematteis 2014, Via do Pico et al 2016.…”