Botanical exchanges: Jean-Jacques Rousseau and the Duchess of Portland

In 1766 Jean-Jacques Rousseau, in exile from France and Switzerland, came to England, where he made the acquaintance of Margaret Cavendish Harley Bentinck, Duchess of Portland. The two began to botanise together and to exchange letters about botany. These letters contain salient statements about Rousseau's views on natural theology, gardens, botanical texts and exotic botany. This exchange entailed not only discussions about plant identifications and other botanical matters, but most important, reciprocal gifts of books and specimens in the manner of gentlemanly scientific correspondence of the period. Rousseau volunteered his services as the Duchess's ‘herborist’ or plant collector, and collected specimens and seeds in her behalf; these were destined for her own extensive herbaria and other natural history collections. Rousseau, who elsewhere denied female talent for science, admired the Duchess's knowledge of natural history, acknowledging his own as inferior. Their correspondence ended when the Duchess sent him the Herbarium amboinense of Georg Rumpf (Rumphius), an important work of exotic botany. Rousseau considered exotic botany to be the antithesis of the domination-free nature from which he derived solace and inspiration.     

Latitudinal variation in a photoperiod response gene in European barley: insight into the dynamics of agricultural spread from ‘historic’ specimens

Between ca. 6000 BC and ca. 500 BC, barley cultivation spread across the continent of Europe from the extreme south to the extreme north. Carbon-dating would suggest that this spread, and indeed the spread of crop cultivation generally, varied in its pace, with ‘delays’ at certain points along its route. Such delays in the spread of agriculture have been explained as resulting from the slow assimilation of agricultural practices by existing indigenous human populations or as the time taken for the crops to adapt to novel climatic conditions, such as altered temperature regimes and day-lengths. A mutant form of the photoperiod response gene, Ppd-H1, causes barley to be non-responsive to long days, while the wild-type responsive form allows plants to flower in response to long days. We sequenced this gene in 65 ‘historic’ barley accessions, from the late 19th and early 20th centuries, in order to explore the potential role of environmental adaptation in the spread of agriculture. We chose to use ‘historic’ material, to complement the richer patterns in extant genetic lines, by spreading the data range in both time and space. Our ‘historic’ barley data shows a latitudinal divide in the Ppd-H1 gene similar to that found in extant lines, but with clearer geographical resolution, and extending northwards into the Arctic Circle. We discuss the implications of our results in relation to the dynamics of agricultural spread across Europe.