Understanding diploid diversity: A first step in unraveling polyploid, apomictic complexity in Amelanchier

Abstract

Amelanchier diploids differ strikingly from polyploid apomicts, in that hybridization among them is rare, and they form taxa that would qualify as species by most species concepts. Knowledge of diploid morphology, phylogeny, and ecogeography provides a foundation for understanding the evolutionary history of polyploid apomicts, their patterns of diversification, and their species status.

Phylogenomics supported by geometric morphometrics reveals delimitation of sexual species within the polyploid apomicticRanunculus auricomuscomplex (Ranunculaceae)

“…Here, we present the first comprehensive phylogenomic and geometric morphometric analysis of all hitherto known sexual species of the Eurasian R. auricomus complex. The delimitation of sexual species and reconstruction of a phylogenetic framework of progenitors is an important step for the classification of apomictic polyploid complexes (Grant, 1981; Burgess & al., 2015; Hörandl, 2018). We ascertained previously reported ploidy levels and sexual mode of reproduction for all taxa by using flow cytometric methods.…”

A reexamination of the North American Crepis agamic complex and comparison with the findings of Babcock and Stebbins’ classic biosystematic monograph

“…To allow comprehensive phylogenetic analysis of the diploid scaffolding of the complex (e.g., Burgess et al, 2015), our field sampling was designed to prioritize detection of diploids. With the exceptions of C. acuminata and C. occidentalis , we searched sites of all historical records of diploids (online Appendix S3), and we identified and searched nearby suitable habitat.…”

The classification of asexual organisms: Old myths, new facts, and a novel pluralistic approach

“…Usually they show a basic structure similar to the classical scheme of Babcock & Stebbins (1938) based on the North American Crepis agamic complex: a few sexual progenitor species hybridized and formed a huge mass of allopolyploid, apomictic derivatives. Several authors have proposed to separate out the sexual progenitor species that are usually found at the diploid or low polyploid level (Grant, 1981;Dickinson & al., 2008;Hörandl & al., 2009;Burgess & al., 2015). These diploid taxa are usually self-sterile, outcrossing and their primary hybrids often exhibit a low female and male fertility.…”

“…The delimitation of sexual progenitor species is important for understanding the origin, evolution, age and phylogenetic relationships of the derivative complexes within their respective genera, and to place apomictic complexes in the framework of the classification of the entire genus (Hörandl & Emadzade, 2012;Burgess & al., 2015;Kirschner & al., 2015;Sears & Whitton, 2016). The sexuals-first concept should not be confused with the purely morphological "main" species concept of, e.g., some traditional Hieracium researchers (see Majeský & al., 2017).…”