Micheli, Pier Antonio

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(b. Florence, Italy, 11 December 1679; d. Florence, 1 January 1737)


Micheli was the son of Pier Francesco Micheli, a laborer, and Maria Salvucci. The boy had only the most elementary schooling (Haller, in 1772, described him as “illiteratus et pauper”), He was, however, interested in plants from childhood, and his native talent won him the respect of, and eventually a prominent position among, the botanists of his time. He obtained the patronage of both the Grand Duke Cosimo III de” Medici and his successor Gian Gastone de’ Medici; the generosity of these two men permitted him to devote himself completely to his studies. Micheli was nonetheless hampered by the lack of an academic degree and never held a post worthy of his talents. He was obliged to content himself with modest positions in the botanical gardens of Pisa and Florence, although he enjoyed considerable contemporary fame among both Italian and foreign botanists and conducted an extensive correspondence with them. He was further influential in founding, with a group of friends, the Società Botanica Fiorentina in 1716 and in the tutelage of a student of great ability, Giovanni Targioni-Tozzetti.

Micheli was a lifelong and tireless collector of plants. His travels for this purpose took him to the provinces of Venetia, Emilia-Romagna, Lazio, Abruzzi e Molise, the Marches, Campania, and Puglia; he was also extremely active in his native Tuscany. In 1708 and 1709 he made collecting expeditions to the Tirol, Austria, Bohemia, Thuringia, and Prussia. He was occasionally accompanied on these trips by Targioni-Tozzetti, who wrote of his skills as a collector:

He was perspicacious and possessed a talent made expressly for natural history, and particularly for botany; his eye was so keen that as soon as he reached a meadow or other place full of grasses, he could immediately distinguish the rarest or most worthy of observation. He was also gifted with an acute critical capacity …, so that he could tell in an instant why other illustrious botanists had been in error, confusing one species with another, or multiplying them [Notizie della vita e delle opere di P. A. Micheli (Florence, 1858), 330].

In the seventeenth and eighteenth centuries the concept of species was crucial to the great botanical task of classification. Micheli’s views on species were in large part derived from those of Joseph de Tournefort, but even more than Tournefort, Micheli realized the need for great caution in the problem of definition. Micheli’s attitude was, in fact, quite close to that of Linnaeus, who expressed his admiration for him. His concern is evident in the first part of his Nova plantarum genera of 1729. In this work Micheli considered some 1,900 species, of which nearly 1,400 were new. The greater number of these new species were thalloplmes—fungi, lichens, liverworts, and mosses—which Micheli classified for the first time. Using two primitive microscopes, he was able to observe, again for the first time, such notable anatomical details as the antheridia and the archegones of mosses and the spores of fungi. He thus discovered, too, the generative function and the anatomy of the mycelium; for this discovery, among others, he may properly be considered the founder of mycology.

The Nova plantarum genera remained unfinished at the time of Micheli’s death, and a considerable amount of the data that he had gathered—particularly material relating to algae, which attracted him as much as did fungi— was therefore never incorporated into it.

In addition to his botanical studies, Micheli was also concerned with zoology, paleontology, and geology. In 1710, while he was botanizing in Campania, he noticed the similarity of the rocks on the islands of Ischia and Procida to those of Vesuvius, and realized that the islands were, in fact, extinct volcanoes. In 1722, recalling this earlier observation, Micheli concluded that the hill of Radicofani in Tuscany and a number of outcroppings in nearby Lazio might also be extinct volcanoes; in 1734 he reached the same conclusion about Monte Amiata, also in Tuscany. His intuition proved to be correct; Micheli’s suggestion represented the first recognition of an extinct volcano far from regions still active volcanically.


I. Orginal Works. Micheli’s major work was Nova plantarum genera… (Florence, 1729). Some of his reports of his journey in 1708–1709 were published posthumously in G. Targioni-Tozzetti, Relazioni di alccuni viaggi fatti in diverse parti della Toscana … (Florence, 1768 1779), IX (1776), 338; X (1777), 134, 159, 177. Several unpublished manuscripts are in the library of the Istituto di Botanica of the University of Florence.

II. Secondary Literature. G. Targioni-Tozzetti, Notizie della vita e delle opere di P. A. Micheli (Florence, 1858), with copious historical notes and extracts from Micheli’s correspondence, edited by Antonio and Adolfo Targioni-Tozzetti, is an excellent source on the life of Micheli and his relations with contemporary scientists.

See also G. Negri, “P. A. Micheli (1679–1737),” in Nuovo giornale botanico italiano, n.s. 45 (1938), lxxxi-cvii; and “P. A. Micheli botanico” in Atti della Societá Colombaria fiorentina, meeting of 27 Dec, 1937, 47–67, and with an extensive bibliography on Micheli; and F. Rodolico, “P. A. Micheli e le prime ricerche sui vulcani spenti,” in Atti dell’ Accademia toscana di scienze e lettere “La Colombaria,” 27 (1962–1963), 353–360.

Francesco Rodolico

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