150 years ago, a Prussian pharmacist named Kowalewski found a flower encased in amber near the Vistula Lagoon in present-day Kaliningrad Oblast, Russia. Then the botanist Robert Caspary characterized it and placed it in the genus Stewartia, which includes only 20 species of modern-day plants. Hence they named it Stewartia kowalewski. Now two researchers have rediscovered the specimen in a drawer of a Berlin science institute. The application of modern science has made it possible to date the specimen with relative accuracy and to identify the plant species to which the largest flower preserved in amber belonged.
Because of its geological location, S. kowaleski must have been surrounded by resin from a tree, believed to be a conifer, 34 to 38 million years ago, according to estimates by the two scientists who analyzed it. The impressively preserved flower preserves all its parts: corolla, petals, sepals, stamens, pistil… and pollen. It will not be crushed or petrified. Amber has held her in her three dimensions. With the help of a scalpel and great care, the researcher Eva-Maria Sadowski from the Museum für Naturkunde in Berlin and her colleague Christa-Charlotte Hofmann from the University of Vienna snatched a few grains of pollen from the fossilized resin. Their analysis, the results of which have been published in the journal Scientific Reports, has prompted them to move the specimen to the Tree of Life.
The cropping of the image allows us to observe in three dimensions the conservation of the flower parts, such as the stamens and the pollen itself. Carola Radke, Museum of Natural History Berlin)
“They described it as Stewartia and we were able to show that the specimen actually belongs to the Symplocos, which is from a different family (Symplocaceae, sweetleaf family) than Stewartia (Theaceae, tea family),” says Sadowski, who specializes in the study of Vegetables in amber. Therefore, they have proposed classifying the flower as Symplocos kowalewski. Beyond mere classification, correct identification allows them to learn more about the environment in which they thrived.
First of all, neither the Stewartia nor the Symplocos are found in Europe today, so vegetation and climate must have been very different 30 million years ago. “Fossil and surviving examples of Symplocaceae indicate that the family thrives in moist mesophyte forests. [un tipo de hoja] mixed in warm temperate to subtropical climates, avoiding dry regions,” explains Sadowski. Thanks to this flower and the remains of other plants also encased in amber, the study’s authors paint a landscape of this “heterogeneous” northern European area, which includes coastal swamps, swamps, riverbank forests, and mixed coniferous and angiosperm forests. [plantas con flores] interspersed with open spaces”. And the German scientist concludes: “Symplocos kowalewskii probably grew in the wooded habitats of this amber forest, but it may also have been associated with swampy habitats.”
The mystery the researchers can’t solve is how such a large flower could be preserved in such good condition. Almost all of the blossoms set in amber have a diameter of a few millimeters, the rest has been preserved broken. The crown of S. kowalewskii reaches 28 millimeters. There are older flowers from 130 million years ago, like those found in the mountains of Cuenca and Lleida, but these were tiny. Although three centimeters across may not seem like much, there is no other flower preserved in the fossil record, let alone in this exceptional state of preservation.
“The extraordinary preservation [de la flor] the biocidal properties of the resin that encased it could have caused this
Eva-Maria Sadowski, research associate at the Natural History Museum Berlin
Researchers have tried unsuccessfully to identify the origin of amber. Aside from the conifers that were present in the region when S. kowalewskii flourished, there are few plant species that secrete plant resin that mineralizes and crystallizes in this way. This would make identification easier, for example, when comparing fossil amber with that of extant species. But, as Sadowski says, “the original amber tree may be an extinct genus that no longer exists.” Also, “as amber is formed, the resin changes its properties, making comparisons with existing resins difficult,” he adds.
For the authors of the study, the preservation of the flower was only possible through the interaction of several factors. On the one hand, as they write in the study, “the exceptional preservation could have been caused by the biocidal properties of the resin that encased them, which would inhibit the degradation process.” Regarding preservation in space, both viscosity and necessary must play a role have played, but not excessive tension on the resin lest it crush or break the flower. In addition, the amber enveloped the flower at the moment of anthesis, i.e. during flowering. Without this chance there would have been no pollen to identify Symplocos kowalewski.
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