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Despite its status as a highly-prized and coveted fungi in gastronomy, many aspects of the subterranean life cycle of the Burgundy truffle (Tuber aestivum) are still unknown, because in situ observations of the formation and maturation of truffle fruitbodies remain difficult. Here, we adopted a suite of archaeological fine-scale excavating techniques to provide unique spatiotemporal snapshots of Burgundy truffle growth at three sites in southern Germany. We also recorded the relative position, fresh weight, maturity level and genotype composition of all excavated fruitbodies. Varying by a factor of thousand, the fresh weight of 73 truffle ranged from 0.1 to 103.2 g, with individual maturity levels likely representing different life cycle stages from completely unripe to fully ripe and even decaying. While only a slightly positive relationship between fruitbody weight and maturity level was found, our results suggest that genetically distinct specimens can exhibit different life cycle stages at the same period of time and under the same environmental conditions. We therefore argue that truffles are likely able to grow, mature and ripe simultaneously between early summer and late winter of the following year. Our case study should encourage further eco-archaeological truffle excavations under different biogeographic settings and at different seasons of the year to gain deeper insights into the fungi's subterranean ecology. The expected cross-disciplinary findings will help truffle hunters and farmers to improve their harvest practices and management strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

The Burgundy truffle (Tuber aestivum Vittad.), an ectomycorrhizal fungus living in association with host plants, is one of the most exclusive delicacies. The symbiosis with deciduous oak, beech, and hazel dominates our concept of truffle ecophysiology, whereas potential conifer hosts have rarely been reported. Here, we present morphological and molecular evidence of a wildlife T. aestivum symbiosis with Norway spruce (Picea abies Karst.) and an independent greenhouse inoculation experiment, to confirm our field observation in southwest Germany. A total of 27 out of 50 P. abies seedlings developed T. aestivum ectomycorrhizae with a mean mycorrhization rate of 19.6 %. These findings not only suggest P. abies to be a productive host species under suitable biogeographic conditions but also emphasize the broad ecological amplitude and great symbiotic range of T. aestivum. While challenging common knowledge, this study demonstrates a significant expansion of the species' cultivation potential to the central European regions, where P. abies forests occur on calcareous soils.

Wilhelm Weygandt's Uber die Mischzustände des manisch-depressiven Irreseins (On the Mixed States of Manic-Depressive Insanity) describes and conceptualizes mixed states of mood, behavior, and thinking commonly found in manic-depressive disorders. These ideas emerged from Weygandt's service in the 1890s at the Psychiatric Clinic of the University of Heidelberg, directed by Emil Kraepelin. In the sixth (1899) edition of Kraepelin's influential textbook, the concept of manic-depressive illnesses underwent a fundamental shift from a complex group of syndromal subtypes to a single integrated disorder, widely known from the 1921 English translation of the eighth (1920) edition. In the 1899 edition, Kraepelin acknowledged Weygandt for a new section on mixed manic-depressive states within the new integrated view of manic-depressive disorder. We provide biographical notes on Weygandt, a little-known but historically important figure, as well as the first English translation of his monograph and interpretive summaries of his findings. We also consider whether Weygandt's important insight that the same person could be both manic and depressed not only at different times but even at the same time served as an important stimulus to Kraepelin's unified manic-depressive disorder concept, which survives as bipolar disorder a century later.