Swiss bryologist and palaeobotanist, Léo Lesquereux was an expert in the peat bogs of Europe and North America and resided for many years in Columbus, Ohio. Born in the town of Fleurier, Lesquereux was a keen explorer as a boy and toured the surrounding Neuchâtel region in search of plants. One day, while out studying the vegetation of a mountainous region, he slipped off a cliff edge and fell some 100 metres, hitting many outcrops on his descent and finally becoming entangled in some branches. It was here that his family found him and he was thought to be dead, but after some weeks bed-ridden he recovered and continued his exploration undeterred.

Lesquereux always had a particular interest in peat bogs and spent much of his spare time studying their structure and composition. Destined by his family for the church, his education at Neuchâtel university was cut short by a lack of funds when he was 19 years old and he found himself having to earn a living by teaching French. Working at a young ladies academy in Eisenach he was to marry one of his pupils, Sofia von Walffskeel, with whom he would have three sons and a daughter. Lesquereux was named principal of La Chaux-de-Fonds College, but unfortunately he suffered from an illness and, despite travelling to Paris in search of a cure, became entirely deaf at the age of 26. Forced to abandon his teaching career he instead learned to engrave watch cases and make springs (the family business) and was supported greatly by his wife in this venture for she also learnt the trade. For 12 years Lesquereux worked in this capacity, but continued to study his beloved peat bogs and began to produce works on the associated moss flora and fossil plants, publishing a catalogue of Swiss mosses in 1845. The same year the King of the Prussian Empire (under which Neuchâtel fell at this time) was looking for a researcher to help in the restoration of the region's bogs due to concerns about the fate of their timber industry. Lesquereux was chosen and commissioned to study the peat swamps of Jura, the coasts of the North and Baltic Seas, and later Denmark, Sweden and Norway.

After the revolution of 1847, Lesquereux found himself without a job and took the decision to leave Europe with his family the following year. Travelling to North America they settled in Ohio and, after a period of considerable poverty, managed to resume the family business with the help of Lesquereux's sons. This allowed him to continue with his study of peat bogs and in time he produced papers on the fossil coal flora of Arkansas, Illinois, Mississippi, Dakota and California. His most important palaeobotanical work, Coal Flora of Pennsylvania and the United States (1880) was aided by his work for the State Survey, which he was involved with from 1875.

At the same time continuing his work as a bryologist, Lasquereux was employed by William S. Sullivant to undertake a collecting expedition to the Southern states and from this work he produced an exsiccatae series of 416 species entitled Musci Boreali-Americani in 1856. Over the years he also studied the specimens of other collectors, such as C. Wright's plants from the North Pacific Exploring Expedition and H.N. Bolander's material from California, publishing accordingly. His key bryological publication, A Manual of the Mosses of North America, was finally brought out in 1884 but by this time Lesquereux's eye sight had deteriorated considerably and he required the help of both Sullivant and T.P. James to see it to completion. A shy and modest man, Lesquereux was acutely aware of his deafness and, despite the fact that he was able to converse freely with his friends and could lip-read in three different languages, he was often self-deprecating. This was reflected in his scientific endeavours and despite his pioneering work on boreal peat bogs, his name is not, perhaps, as well recognised as his work would merit.

Sources:
Anon, 1890, "Obituary notice of Leo Lesquereux", Proceedings of the American Philosophical Society 28: 65-70
C.R. Barnes, 1890, "Leo Lesquereux", Botanical Gazette, 15: 16-19
H.B. Humphrey, 1961, The Makers of North American Botany: 141-144.