(b. Angers, Maine-et-Loire, France, 12 May 1861: d. Vitrac [near Sarlat], Dordogne, France, 5 August 1936)
Sauvageau came from a family of landowners and lawyers that had been established for several centuries in Anjou. After completing his secondary education at a collège libre in Angers, he entered the University of Montpellier. He obtained his licence ès sciences physiques and licence ès sciences naturelles in 1884 and immediately became an assistant to Charles Flahault, who held the chair of botany at the university.
Having successfully passed the agrégation, in 1888 Sauvageau was named professor at the lycéein Bordeaux. He left this post the following year to prepare a dissertation at the Muséum National d’Histoire Naturelle in Paris. He worked in the laboratory of P. van Tieghem, who encouraged most of his students to investigate problems in plant anatomy. Thus it is not surprising that Sauvageau’s thesis (1891) was entitled “Sur les feuilles de quelques Monocotylédones aquatiques.” In this work Sauvageau emphasized marine species: and because his research had taken this direction, Flahault introduced him to Édouard Bornet. The latter started him on the study of marine algae, and Sauvageau soon gave up his anatomical research to concentrate on this group.
Shortly after earning his doctorate, Sauvageau was appointed maître de conférences at Lyons and then professor at the Faculty of Sciences of Dijon. In 1901 he became professor at the Faculty of Sciences of Bordeaux, a post that he held until his retirement in 1932. Sauvageau was married to Marie-Louise Michelot, by whom he had one daughter.
Sauvageau’s scientific work brought him many honors. He was elected corresponding member of the Académie des Sciences (1918), and he was a member of numerous foreign scientific academies and societies.
In his initial research, Sauvageau studied the anatomy of aquatic monocotyledons, mycology, phytopathology, and, particularly, diseases of the grape. But the bulk of his work was devoted to marine algae and in fact was concentrated almost exclusively on the study of Phaeophyceae. The few papers that were not concerned with this group dealt with the marine flora of the Gulf of Gascony, the coloration of oysters by the blue diatom, gelose (agar), the commercial uses of marine algae, and the iodine-containing cells (ioduques) of Bonnemaisoniaceae.
Sauvageau’s first research was concerned with Ectocarpaceae. He showed in particular the great variety of their reproductive organs (1892–1897). He observed the isogamous and anisogamous copulation of certain flagellate cells produced by these organs and also noted the frequency with which they develop parthenogenetically.
He then studied Myrionemaceae (1898) and Cutleriaceae (1899). In the course of this research he confirmed and extended the observations of Johannes Reinke and Paul Falkenberg on the heteromorphic life-cycle of Cutleriaceae and demonstrated that the alternation of generations of Cutleria-Aglaozonia is not absolutely constant.
In “Remarques sur les Sphacelariacées” (1900–1914), a series of papers totaling more than six hundred pages, Sauvageau described the complex anatomical structure of the various genera of this family, discussed their reproduction and development, and established a classification for them. Also, he published works on the various forms of Fucus and on the Cystoseira of the Mediterranean and the Atlantic (1913); these works are model systematic and ecological studies.
It was known that some certain Phaeophyceae produce only unilocular organs and appear to be deprived of sexuality because their zoospores are incapable of copulation. This condition is the case of the Laminariaceae, whose mode of reproduction was still unknown as late as 1915. In that year Sauvageau announced that the zoospores of Saccorhiza bulbosa give rise to filamentous microscopic plantlets. He further stated that some of these plantlets produce antherozoids while others produce oospheres, and he concluded that the plantlets are actually forms of prothallia. He then extended his investigations to other Laminariaceae found on the coasts of France and showed that this family, type of the order of Laminariales, is characterized by a type of alternation of generations that was previously unknown among the Phaeophyceae but is comparable to that encountered among the ferns.
Sauvageau also showed that this type of alternation of generations is exhibited by other Phaeophyceae, namely, Dictyosiphon (in which the prothallium produces isogamous gametes) and Carpomitra (in which the female prothallium is regularly apogamic). These two genera became the model types of two new orders: Dictyosiphonales and Sporochnales.
Sauvageau showed that among other types of Phaeophyceae, the discoid or filamentous microscopic plantlets emerging from the developing zoospores are not sexed. Thus he concluded that this stage of development, which he called adelophyceae in contrast to that of macroscopic plants (delophyceae), is not that of a prothallium. Instead, this stage produces numerous zoospores that, if placed in culture, are capable of reproducing several generations of microscopic plantlets before reaching (under favorable conditions) the delophycean stage. Sauvageau gave the name plethysmothalli to these microscopic plantlets, which have no analogues among the other plants.
Sauvageau’s discoveries, which were made with simple culture techniques, greatly elucidated the extremely complex cycles of the brown algae. More concerned with facts than with theories, Sauvageau did not attempt to derive general conclusions from his many discoveries. Yet, these discoveries form the basis of all our present knowledge concerning Phaeophyceae—its classification and the evolution of its reproductive cycles.
I. Original Works. Among Sauvageau’s works are “Remarques sur la reproduction des Phéosporées et en particulier des Ectocarpus,” in Annales des sciences naturelles, 8th ser., 2 (1896); “Sur quelques Myrionémacées (premier mémoire),” ibid., 5 (1898); “Les Cutlériacées et leur alternance de générations,” ibid., 10 (1899), 265–362; Remarques sur les Sphacélariacées, published in parts in Journal de botanique. 14–18 (1900–1904) and separately (Bordeaux, 1904, 1914): “A propos de Cystoseira de Banyuls at de Guethary,” Bulletin de la Station biologique d’Arcachon, 14 (1912); “Recherches sur les Laminaires des côtes de France,” Mémoires de l’Académie des sciences, 56 (1918); and Utilisation des Algues marines (Paris, 1920). A large number of papers was published in Bulletin de la Station biologique d’Arcuchon from 1905 to 1936.
II. Secondary Literature. See the obituary by P. Dangeard in Bulletin. Société botanique de France, 84 (1937), 13–18; and Bulletin de la Station biologique d’Arcachon, 34 (1937), 5–59; and J. Feldmann, “L’oeuvre de C. Sauvageau (1892–1936),” in Histoire de la botanique en France (Paris—Nice, 1954), 212–217.