Biography Dr. Leon Croizat-Chaley

The botanist Léon Croizat (1894-1982) was one of the most controversial figures in the history of evolutionary biology of the twentieth century. As a result of his reflection on the evolution and geographical distribution of living beings, he became critical of modern synthetic theory. Croizat not only departed from the dispersalist explanation of the geographical distribution of living beings, but from the Darwinian evolutionary explanation, which assigns to natural selection the preponderant role as an agent of organic change. Croizat's ideas are attractive to some biologists, because they suggest the possibility of a new, more comprehensive and comprehensive evolutionary synthesis that combines the concepts of space, time and form (Morrone, 2000b; Grehan, 2001b). Through his biogeographic proposals (Croizat, 1952, 1958, 1964, 1976), even more after his amalgamation with Hennig's phylogenetic system to originate cladistic biogeography (Nelson and Platnick, 1981), this author contributed significantly to the development of a new vision of evolutionary biology.

Several authors have highlighted biographical aspects of Léon Croizat (Croizat, 1982; Craw, 1982, 1984a, b; Hull, 1988; Zunino, 1992; VJ Croizat, 1997; Llorente Bousquets et al., 2000, 2003; Morrone, 2000a; Grehan , 2001b). Croizat was born in Turin (Italy) on July 16, 1894 and died in Coro (Venezuela) on November 30, 1982. His family originally came from Bresse, France. His father, Victor Croizat, was born in Chambérry, and his mother, Marie Chaley, was a native of Lyon (Texera, 1998). His father was a wealthy industrialist who dedicated himself to oil exploitation in Italy and Romania, and stood out as a pioneer in the electrical and automotive industries. When Leon was six years old, his parents divorced, and by the year of his father's death (1915) the family was bankrupt. From a young age, Croizat became fond of nature. He frequently visited the house of Count Peracca, an amateur herpetologist from Turin who belonged to Daniele Rosa's circle, where he spent hours in his greenhouse, between giant iguanas and turtles from the Galapagos Islands. There he began to be interested in the study of taxonomy and evolution. However, his father was opposed to his dedication to the natural sciences, which he considered a hobby. Craw and Heads (1988) have highlighted the relevance of this "Turin connection", which would imply recognizing Rosa - author of the theory of hologenesis (1918) - as one of Croizat's intellectual precursors. However, according to Croizat (1978: 60; see also Luzzatto et al., 2000), he discovered Rosa's work only in 1963, when Colosi sent him a copy of the Ologenesi. During World War I, Croizat served in the Italian army, where he became Captain of the Infantry. He had two children: Victor, born in Tripoli (Libya) in 1919, and Georgette, born in Turin in 1921. At the end of the war, he obtained a doctorate in jurisprudence at the University of Turin (1919) and began working with a friend in a textile mill, but the rise of fascism forced him to emigrate to the US In 1924 he arrived in New York, while his wife and children remained for a time in Ceyzerieu (France), to travel later to meet him. During his early years in the U.S., Croizat went through some economic hardships, earning a living through various occupations; later he began to paint watercolors and after participating in several art exhibitions he got some success. Towards the end of the 1920s, it enjoyed economic solvency, but when the market for works of art declined, mainly due to the stock market crash of 1929, Croizat and his family had to return to Europe, to try their best in Paris. There they found that the situation was even worse, especially since a few years before Croizat had nationalized American and did not get a work permit, so they decided to return to New York. This time, Croizat got a job identifying plants for a topographic inventory that was being carried out in the New York parks. While performing this task, he frequently visited the Botanical Garden of the Bronx, where he met its director, E. D. Merrill. This would have to be fundamental for his future, since when he assumed the direction of Arnold Arboretum of Harvard University in 1937, he hired Croizat as a technical assistant. There Croizat had at his disposal an important botanical garden, a huge herbarium and a specialized library. In the latter he spent hours, reading and translating taxonomic works, since as part of his training, Croizat was a polyglot: French and Italian were his mother tongues and he also read, spoke and wrote fluently in Latin, Spanish, Portuguese, English, German , Russian and Greek.

At Harvard, Croizat began publishing botanical works on systematics of cactaceae and euphorbiaceae. On one occasion he sent a manuscript to be published in the Arboretum magazine, in which he criticized the work of an influential botanist. The editor of this magazine rejected the manuscript because he considered the criticism inadequate. However, the work was subsequently published in another medium. This fact, added to the peculiar character of Croizat, were reasons for progressively beginning to generate antipathy among those around him. However, Merrill kept him in his position, although since 1939 he was under the orders of Alfred Rehder. In 1946, when Merrill was replaced as director of the Arboretum, it took little time for Croizat to be fired. During his years at Harvard, he accumulated about 350 notebooks with notes taken during his readings and his work in the herbarium, "a true vademecum of botanical problems," as he would say in his personal presentation to Henri Pittier (Texera, 1998). Finding it difficult to find a new job in the United States, Croizat requested information from Henri Pittier about the possibility of helping him in his botanical work in Venezuela. Pittier knew Croizat's work, since he had made taxonomic determinations of the euphorbiaceae that the Swiss had sent to the United States from the incipient National Herbarium of Venezuela. On October 5, 1946 he informed him that, in view of his position as head of the Botanical Service and the support of friends in the government, he could offer him a temporary job. In March 1947, Croizat arrived in Venezuela and began working in the Botanical Service of the Ministry of Agriculture and Breeding, in Caracas. In a 1948 report, Pittier expressed the following about Croizat: “botanist versed in taxonomy, specializing in the study of euphorbiaceae, cacti, lentiburlariaceae, droseraceae and Saraceniaceae. In addition to his duties as botanist of this department, he is officially in charge of the botanical part in the Tacagua Reforestation Project ”(Texera, 1991). A transcript of the aforementioned document (Texera, 1998) reveals that Croizat would have arrived in that country for a short time, but in view of the enthusiasm aroused by Venezuelan nature he decided to stay longer. That lapse would be nothing less than the 34 years that were left of life! In Caracas, Croizat was professor of botany at the Faculty of Agronomy of the Central University of Venezuela. In 1950, he terminated his contract with the Botanical Service and moved to Mérida, where he was admitted as an ordinary professor of botany and ecology at the School of Forest Sciences of the University of Los Andes. There he studied the Andean xerophilous belt (Croizat, 1954), where he showed his inclination for the phytogeographic comparison of these biological enclaves, and which later would bring to discussion on the occasion of a visit to the Andean arid areas of Chile (Croizat, 1961). In 1951, the Venezuelan government appointed him the official botanist of the Franco-Venezuelan Expedition that first reached and explored the sources of the Orinoco River. This period was decisive in the direction that his life would take in the near future. One of the testimonies of Croizat's participation in this adventure was the Venezuelan entomologist Anduze (1960). On November 27, 1951, a small group of expeditionaries reached a point where by convention it has been said that the Orinoco River is born, while evacuated personnel (Croizat included) were still fighting on their way back. In December Croizat was back in Caracas, and the following year he was decorated for his participation in the mission (along with the rest of the participants) with the Order of the Liberator in the degree of Knight. At that time he divorced his first wife and married Hungarian immigrant Catalina Krishaber, a landscape and horticultural architect, whom he met in that city and with whose financial support he was able to devote the next 30 years to work and publish profusely. They lived until 1975 in a small house of the Chapellín Urbanization, in the northeast of Caracas, where Catalina was in charge of attending a nursery of succulent plants and cacti called “Cactilandia”. In that place Croizat deepened his studies and wrote most of his work. Throughout his life, Croizat published about 300 scientific papers and seven books, totaling more than 15,000 printed pages (Nelson, 1973; Heads and Craw, 1984; Morrone, 2000a). His works refer to botanical systematics and biogeography of the Eastern region, Africa and America. His first book was the Manual of phytogeography, published by the Junk publishing house in The Haya in 1952. Six years later Panbiogeography appeared, thanks to the financial support of a Venezuelan admirer whose name remains anonymous. In 1962 he published Principia botanica and in 1964, Space, time, form: The biological synthesis, both edited by himself. In 1975 the Ministry of Defense of Venezuela printed its Relationship of the wars of Hannibal and Rome, 218-202 a. C., a historical work. The following year, the Library of the Academy of Physical, Mathematical and Natural Sciences of Venezuela published its analytical and synthetic Biogeography of the Americas. Finally, in 1981, a series of consecutive essays that Croizat had written about human geography for the magazine Integración y Progreso (Caracas) was compiled in a book, and is entitled The Pacific Ocean in the prehistory of the Americas. In 1970, Croizat and his wife assumed the direction of the Xerófito Botanical Garden of Coro, a city located 453 kilometers west of Caracas. Croizat died of a heart attack on November 30, 1982, at 88 years of age. Catalina Croizat died on July 29, 1997, when she was 89 years old. The remains of both rest in the public cemetery of Coro.


MORRONE, J. J. (2004). Homología Biogeográfica. Universidad Nacional Autónoma de México.