Editorial

This first issue of 2019 is the opportunity to thank all the key people who have contributed to making Botany Letters an exciting Journal, with an impact factor that reached 1,342 in 2018. This is largely to be put to the credit of the board of editors who spend a significant amount of volunteer time and all the best competencies in their respective fields of expertise to monitor the process of editing the manuscripts. However, the journal could not exist without the major contribution of all the anonymous experts who in their fields have contributed to help the authors improve their research presentation. On behalf of the Société Botanique de France, we want to thank all of them for their contribution in 2018. The list of experts is inserted at the end of this issue. Those who need a certificate to testify to this activity and have not got it yet can ask it on their author/expert centre on our platform.

In 2019, for the third year, the Société botanique de France has awarded the Jussieu prize to what was judged as the best manuscript published in 2018. The jury is composed of six editors including the two editors-in-chief. This year the prize has been awarded to Sandrine Moja, from Saint-Etienne University for her research, “A Comparative Study of Terpene Composition in Different Clades of the Genus Lavandula”, published in issue 165(3–4) (Guitton et al. 2018). This research aimed at documenting the compound diversity of Lavandula essential oils, and most notably terpene variation amongst species. The authors demonstrated that terpene composition is not appropriate for phylogenetic reconstruction and chemotaxonomy in Lavandula, but showed that terpene diversity allows for distinguishing between subgenera. Based on the results obtained, the authors propose evolutionary hypotheses and future work directions relative to the putative ecological role of these terpenes in other species and to terpene biosynthesis studies in Lavandula. This research shows a comprehensive approach to systematic, plant traits, phytochemistry and genetics, which the jury greatly appreciated. The research prize of €5000 is designed to help the team to pursue their research.

Some changes have been made in the editorial board. We need to thank here the editors who have left our team, Farid Bensettiti, Jinping Hua, Diana Jolles, Marc Jullien and Jill Rapson. The editorial board want to welcome Tatiana Texeira de Souza-Chies, professor in the Botany Department of the Federal University of Rio Grande do Sul (UFRGS) in Porto Alegre in Brazil. There, Tatiana conducts research on genetic and evolution of monocots and her competences will reinforce our capacity in systematic botany, genetic and in the botany of Southern America.

Florian Jabbour, one of our editors, has volunteered to join the two editors-in-chief as editorial assistant to reinforce our overall capacity in making Botany Letters the exciting journal we are committed to.

This issue contains three contributions selected from those presented at the thirty-sixth Symposium of the Association des Diatomistes de Langue française (AdLAF) held in Dijon. This French-speaking society promotes diatom research and organizes an annual symposium for facilitating the exchange of information between diatom experts.

Despite the largely recognized role of diatoms in ecosystems (e.g. Schoefs, Hu, and Kroth 2017), the total number of taxa remains elusive and very regularly new genera and species are reported (Beauger, Serieyssol, and Schoefs 2015). In this issue, Beauger et al. (2019) describe a new species of the genus Pseudostaurosira. It was found in a hydrothermal spring of the Massif Central in France. The new species presents morphologic characteristics such as the size, the density of striae and the presence of volae allowing separation from the other species. Depending on the environmental conditions, diatoms may be part of assemblages. The study of Lai et al. (2019) is dedicated to the thermo-mineral springs of Sardinia, an unexplored ecosystem from the biota and ecology point of views. In this article, a total of 55 genera and 132 diatom species are reported. Despite the 62 taxa common to other thermal springs of the Mediterranean area, significant differences in the species composition among all substrates were highlighted. Among the unique characteristics of diatoms, the shape and the decoration of cell walls is not the least. In an environment favouring the development of diatoms and their assemblages, the morphologic properties of the cell wall are very stable and usually used for taxonomy. Changing the environmental parameters such as salinity (Marchand et al. 2018) or heavy metal (Gautam et al. 2017) may significantly modify this geometry, that can then be used as a bioindicator of stress conditions. Cerisier et al. (2019) present a method to quantify the deviation induced by a stress. The method is based on a geometric morphometric approach to evaluate the degree of deformities induced in the diatom cell wall. The statistical analyses not only allowed the authors to discriminate between normal and deformed individuals, but also revealed a gradient in the intensity of the deformities.