Botanists Untangle a Century of Confusion in the Fleabane Daisies of Türkiye

In the quiet, meticulous world of plant taxonomy, a single dried specimen pressed onto a sheet of paper more than a century ago can decide whether a species is real, a synonym of something else, or a name that has been misapplied by generations of botanists. That is precisely the stakes in a new study published in the journal Plant Biosystems, in which researchers Batıkan Günal and Gürkan Semiz of Pamukkale University in Denizli, Türkiye, have clarified the nomenclature of three names in the daisy genus Erigeron: Erigeron cilicicus, Erigeron pycnotrichus, and Erigeron olympicus. Their work, grounded in the International Code of Nomenclature for algae, fungi, and plants, designates lectotypes for all three names and formally transfers one species from a different genus back into Erigeron, resolving uncertainties that have clouded the classification of these fleabane daisies in Türkiye and neighboring regions.

Erigeron, commonly known as fleabane, is one of the largest genera in the daisy family, Asteraceae, and belongs to the tribe Astereae. The genus is notoriously difficult, encompassing hundreds of species distributed across nearly every continent, with particular centers of diversity in mountainous regions of western North America and southwestern Asia. Molecular phylogenetic studies over the past two decades, including analyses of nuclear ribosomal DNA and chloroplast sequences, have repeatedly shown that Erigeron and its close allies in the subtribe Conyzinae form a complex evolutionary radiation in which morphology alone is a poor guide to species limits. In this context, getting the names right is not pedantry. Every floristic survey, conservation assessment, ecological study, and chromosome count depends on names that unambiguously refer to the same plants their original authors intended.

The anchor of that unambiguity is the type specimen. Under the nomenclatural code, every species name is permanently attached to a type, a single specimen or illustration that serves as the objective reference point for the name. When an author describes a new species without designating a holotype, or when the original material turns out to include more than one gathering, later botanists must select a lectotype from among the eligible specimens. This process, called lectotypification, is one of the least glamorous but most consequential activities in botany. Choose the wrong specimen, and a name can be shifted onto an entirely different plant, cascading through checklists and herbaria worldwide. Günal and Semiz undertook exactly this kind of detective work, critically evaluating the protologues, the original published descriptions, along with relevant taxonomic literature and herbarium specimens, both physically examined and digitally available.

The first name they addressed was Erigeron cilicicus, a species associated with the Cilician mountains of southern Anatolia. By assessing the original description against surviving historical material, the researchers designated a lectotype preserved at the herbarium of the Muséum National d’Histoire Naturelle in Paris, abbreviated P, one of the great repositories of nineteenth-century botanical collections. Significantly, their analysis established that this lectotype corresponds to material held at the herbarium of the University of Natural Resources and Life Sciences in Vienna, abbreviated WU, that had been treated under the name Erigeron argaeus. In practical terms, the two names now converge on the same plant, and the synonymy between them is stabilized by an objective type rather than by opinion.

The second case proved more intricate. Erigeron pycnotrichus traces back to the Austrian botanist Friedrich Vierhapper, whose 1906 monograph of the alpine Erigeron species of Europe and western Asia remains a foundational reference for the group. Vierhapper had described the plant under the genus Trimorpha, a segregate genus that later authors have variously accepted or merged into Erigeron. Günal and Semiz designated a lectotype at the Royal Botanic Gardens, Kew, abbreviated K, and found that it is equivalent to material at WU labeled Trimorpha cappadocica as well as to an illustration by Vierhapper associated with the name Trimorpha isaurica. Because that lectotype illustration is insufficient for the precise application of the name, the authors took the additional step of designating an epitype, a supporting specimen that serves as an interpretive anchor, preserved at the herbarium of Hacettepe University in Ankara, abbreviated HUB. The epitype mechanism exists precisely for such situations, where a type that is technically valid is too ambiguous, in this case a drawing rather than a physical specimen, to settle the identity of a species on its own.

With the types secured, the authors made a formal nomenclatural move: they transferred Trimorpha pycnotricha into Erigeron, publishing the new combination Erigeron pycnotrichus (Vierh.) Günal & Semiz. New combinations are the bureaucratic machinery of taxonomy, required whenever a species is moved between genera while keeping its species epithet. The change matters because the genus-level placement of these plants affects how they are keyed out in floras, how they are retrieved in databases such as Plants of the World Online, and how they are treated in phylogenetic and biogeographic studies of the Astereae, a tribe whose evolutionary history in the Flora Iranica region and across southwestern Asia has been the subject of considerable recent research.

The third name, Erigeron olympicus, refers to a fleabane associated with the mountains of northwestern Anatolia, and its lectotype was designated from material at the Natural History Museum in London, abbreviated BM. Each of the three lectotypifications follows the same underlying logic: the authors compared the original published description with the surviving original material, applied the rules of the Madrid Code, the current edition of the nomenclatural code, and selected the specimen that best secures the name’s traditional and intended usage. The result is a set of three names whose application no longer depends on guesswork or on conflicting interpretations in the secondary literature.

Why should anyone outside herbarium walls care? The answer lies in the geography. Türkiye sits at the intersection of three phytogeographic regions and harbors one of the richest floras in the temperate world, with a high proportion of endemic plants found nowhere else. The alpine Erigeron species treated in this study grow in some of these most sensitive mountain habitats, from the Taurus ranges of the south to the great massifs of the northwest. Recent work by the same research group, including the description of the new species Erigeron akaydinii in 2025, shows that the Turkish fleabane flora is still being actively discovered. Reliable names are the foundation for assessing which of these plants are rare, where they occur, and whether they need protection. A name applied to two different plants can inflate or deflate estimates of rarity and can send conservation resources to the wrong target.

The study also highlights the changing practice of taxonomy itself. The authors drew on both directly examined specimens and digitally available material, reflecting the massive digitization efforts of major European herbaria such as P, K, BM, WU, and the Botanical Museum Berlin-Dahlem, whose collections were partly rebuilt after wartime losses, a history documented in the botanical literature. Digital access to type specimens means that researchers in Ankara or Denizli can now scrutinize material in Paris and London without travel, dramatically accelerating work of this kind. The authors acknowledged the curators of the herbaria B, P, GOET, PR, and WU for granting access to collections and images, and the research was supported by the Scientific Research Coordination Unit of Pamukkale University under project number 2022FEBE022.

In the end, the paper’s conclusions are modest in form but broad in consequence. By designating lectotypes for Erigeron cilicicus, Erigeron pycnotrichus, and Erigeron olympicus, adding an epitype where an illustration alone could not carry the weight, and validating the new combination Erigeron pycnotrichus, Günal and Semiz have removed a layer of nomenclatural fog from a genus that has puzzled botanists since the nineteenth century, when explorers such as Pierre de Tchihatcheff and botanists such as Pierre Edmond Boissier first catalogued the plants of Asia Minor. Future taxonomic studies of Erigeron in Türkiye and adjacent regions, whether based on morphology, cytology, or DNA sequences, can now build on a stable foundation. It is a reminder that in science, as in cartography, the value of a map depends entirely on whether the names on it point to the right places.

Subject of Research: Nomenclatural typification of three Erigeron (Asteraceae) species names from Türkiye

Article Title: Lectotypification of some names in the genus Erigeron (Asteraceae: Astereae)

Article References: Günal, B., & Semiz, G. (2026). Lectotypification of some names in the genus Erigeron (Asteraceae: Astereae). Plant Biosystems, 160(5), Article 289. https://doi.org/10.1007/s44473-026-00298-z

Image Credits: AI Generated

DOI: 10.1007/s44473-026-00298-z

Keywords: Erigeron, Asteraceae, Astereae, lectotypification, nomenclature, taxonomy, Türkiye, herbarium specimens, type specimens, epitype, plant systematics, biodiversity