Category: Uncategorized

TRANSGRESSIVE PROBLEM. "A further problem can arise from transgressive characters, meaning traits that are not seen in either parent. Transgressive characters can already occur at a lower frequency in F1 hybrids, but are frequently reported in later generation hybrids." https://lnkd.in/dK-A3iM View in LinkedIn

REPRODUCTIVE ISOLATION IS KEY. "Regarding description of hybrids as species, an important distinction should be made between reproductively isolated taxa that originated through hybrid speciation (hybrid species) and continuously re-formed hybrids that have distinct features but do not represent a reproductively isolated lineage." https://lnkd.in/dK-A3iM View in LinkedIn

REASSIGNED RHODODENDRON SPECIES. "Together, the two species investigated here have nine described infraspecific taxa: five for R. delavayi, and four for R. irroratum, however, these are all assigned the rank of subspecies." https://lnkd.in/dK-A3iM View in LinkedIn

MISNAMED PLANT SPECIES. "Despite ongoing debate about the overall evolutionary importance of hybridization, the process has been shown to be widespread and relatively common in plants, occurring across many different families and floras. Indeed, Rieseberg (1997) suggested that a worldwide average of 11 % of all described plant species may be hybrids, and that this figure may even be an underestimate." https://lnkd.in/dK-A3iM View in LinkedIn

CONSERVATIVE TAXA ASSIGNMENT. "Hybrids growing in sympatry with their parents cannot necessarily be assumed to have a distinct genepool, and even if certain hybrids show higher fitness than the parents, it needs to be demonstrated that they have the potential to evolve into a coherent group under natural conditions. Before evidence has been collected in this regard, hybrids should rather be recorded as such rather than described as a taxon." https://lnkd.in/dK-A3iM View in LinkedIn

DISTINCT SPECIES PROPERTIES. "Such properties can, for example, include a distinct genepool or adaptation to a different habitat. Furthermore, the group should already share a common evolutionary history or have the potential to diverge." https://lnkd.in/dK-A3iM View in LinkedIn

BELL CURVE IN SPECIATION. "Darwin already noted that there is an evolutionary continuum between varieties and species. This implies that taxa described as varieties (or subspecies) should be groups of individuals that possess evolutionary relevant properties distinguishing them consistently from other members of the species." https://lnkd.in/dK-A3iM View in LinkedIn

INTERMEDIATE VERSUS PARENTAL. "While intermediacy is often the expected state in hybrids, it has been shown when averaging over several studies that only about half of the characters in hybrids for interspecific crosses were intermediate, with other characters approaching the morphology of one of the parents." https://lnkd.in/dK-A3iM View in LinkedIn

INTERMEDIATE PHENOTYPES. "Other qualitative characters, on the other hand, either tended towards the morphology seen in one of the parents (stamen hairs were mostly present in the intermediates, as in R. irroratum; ovary glands were consistently absent, as in R. delavayi or showed a combination of intermediate and parental characters (styles were either hairy, or glandular and hairy; and ovaries were either hairy, intermediate, or densely hairy." https://lnkd.in/dK-A3iM View in LinkedIn

STRONG PHENOTYPE DIFFERENCES. "Several characters were identified that could distinguish between the species. The quantitative characters that showed high discrimination potential ‘flowers in inflorescence’, ‘stigma width’, ‘corolla (width/length)’ and also ‘leaf (dist apex-mid/length)’, tended towards intermediate values for the hybrids. As quantitative characters are generally considered to be under polygenic control, this can be expected." https://lnkd.in/dK-A3iM View in LinkedIn