(b. Azay-le-Rideau, France, 12 September 1815; d. Hyères, France, 22 December 1885)
Tulasne studied law in Poitiers with the intention of becoming a solicitor. In 1839, however, he inherited a considerable sum of money from his father and went to Paris to join his brother Charles, who was conducting medical studies there. The two brothers decided to give up their previous careers and to devote themselves to a life of botany, Christian religion, and charitable activities. They cooperated in these efforts until 1884, when Charles Tulasne died. Of the fifty-seven botanical works that Louis René Tulasne eventually published, his brother, who was also a talented and dexterous draftsman and illustrator, assisted him in the composition of fifteen.
In Paris, Tulasne attended the lectures of Brongniart, A. de Jussieu, and J. H. Léveillé and became a collaborator of Auguste de Saint-Hilaire at the Muséum National d’Histoire Naturelle. His first memoir, on the structure of the Elaphomyces fungi, was published in 1841. He then went on to study the results obtained by the British scientist Miles Berkeley, who had demonstrated that there are two fruiting forms in four genera of Gasteromycetes. He confirmed Berkeley’s findings and generalized them in a series of ten memoirs, of which the last, Fungi hypogaei (Paris, 1851), remains one of the foundations of the modern study of this group.
At this time the Uredinales and Ustilaginales – the rusts and smuts that cause serious plant diseases– were little known, and some taxonomists thought them to be related to the Gasteromycetes. Tulasne began to study these parasites and was able to determine by experimentation that in them the germination of teleutospores gives an intermediate promycelial stage, homologous to a basidium, which produces basidospores. Cell continuity, he established, was in these instances of prime importance. He then demonstrated the various fruiting forms borne in the growth of a single thallus in many species. He published, in addition to an important memoir on Ustilaginales, a precise explanation of the life-cycle of rye ergot (Claviceps purpurea), descriptions of the genus Hypoxylon, and various notes about Erysiphaceae (the powdery mildews).
Tulasne also did research on the reproduction and physiology of lichens, demonstrating that they display a filamentous habit rather similar to the mycelium of a fungus in their first stages of growth. Working with almost every European species of lichen, he determined the presence of spermatogonia and pycnidia in them and simultaneously succeeded in cultivating some species through sowing spores. In recognition of this work, as well as his important contributions to mycology, Tulasne was in 1854 elected to the Académie des Sciences.
Although his scientific reputation was based largely upon his work on cryptogams, Tulasne conducted other significant research on flowering plants. In 1849, having made a thorough study of the important herbaria of Paris and London, he brought out a paper on the Podostemeae, a group of plants similar to the mosses and ferns in appearance but belonging to a higher order because of their dicotyledonous embryos. He also published, between 1853 and 1855, two memoirs on American Leguminosae, four books on the flora of Colombia, a series of notes on the flora of Madagascar, four papers on the Monimiaceae, a work on American Gnetaceae, and a memoir, with descriptions of new species, on the two American genera Antidesma and Stilaginella.
Tulasne’s major publication, written with his brother, was Selecta fungorum carpologia, published in three volumes between 1857 and 1865. At its completion, when he was fifty years old, Tulasne believed that his health was failing. He therefore presented his rich herbarium to the Muséum National d’Histoire Naturelle, gave his library to the Paris Université Catholique, and retired with his brother to the south of France, where they lived quietly for the rest of their lives.
On Tulasne and his work, see E. Bornet, “Notice sur M. L. R. Tulasne,” in Comptes rendus hebdomadaires des séances de l’Académie des Sciences, 103 (1886), 957 – 966; M. Chadefaud, “Mycologie,“in A. Davy de Virville, Histoire de la botanique en France (Paris, 1954), 219 – 234; and P. Duchartre, “Notice sur M. L. R. Tulasne et sur son oeuvre botanique,” in Comptes rendus hebdomadaires des séances de l’Académie des Sciences, 101 (1885), 1438 – 1444.