Agardh, Jacob Georg

(b. Lund, Sweden, 8 December 1813; d. Lund, 17 January 1901)

botany.

As the son of the prominent botanist Carl Adolph Agardh, Jacob had exceptional opportunities to acquire scientific experience at an early age. He was only fourteen when he accompanied his father on an important algological expedition to the Adriatic, and he showed both keen powers of observation and a marked aptitude for collecting. He also began to do research on phanerogams and cryptogams. Agardh followed in his father’s footsteps and soon gained international renown as an algologist, specializing in sea algae. Agardh was basically a taxonomist, but his scientific approach was different. When Agardh began his scientific career, the conditions for research were better (through the improvement of microscopy) than in his father’s time.

Agardh’s first research on algae dealt with the germination process in some species. He studied their development and explained the nature of the swarm spores, which had previously been unclear. At the same time he began to observe how such external conditions as depth of water and currents influenced the appearance of the various species. This was of primary importance for the understanding of the taxonomic characteristics.

Agardh soon acquired firsthand knowledge of numerous types of algae by undertaking an extensive field trip to the Mediterranean and through herbarium studies in the large collections at the Muséum d’Histoire Naturelle in Paris, among others, which had also been studied by his father. His important Algae mans Mediterranei et A driatici (1842) dealt with his new findings and contained his first work on the taxonomy of the Florideae, which was to become his most important field of research. The point of departure for his research on the differentiation of the classes of the Florideae was the structure of the reproductive organ and the structure of the cystocarp. Although his criteria are no longer considered definitive, many of the groups he differentiated are still valid. His magnum opus as an algae taxonomist was Species, genera et ordines algarum in six volumes, published during the course of more than half a century (1848–1901). It contains all the then known species of the Florideae and all the known species of Fucaceae (brown algae) as well as their description and a general morphological survey, all in accordance with the Swedish Linnaean tradition. When the plant physiologist Julius Sachs published a critical appraisal of Linnaeus’ contribution in his history of botany, Agardh was one of Linnaeus’ most ardent defenders. Agardh’s interest in taxonomy encompassed the entire plant kingdom, and he developed his ideas in Theoria systematis plantarum (1858). Here he reveals himself as an idealist, as were many leading scientists during the pre-Darwinian era. He interprets the natural relationship between various genera, as well as between other taxa, not as a phylogenetic one but as one dependent on the premise that all genera within a family reflect the same prototype, that is, a pattern according to which the Creator worked when He created the various species.

Following the trend of his contemporaries, Agardh combined idealism with certain evolutionary beliefs. Hence, he considered that each species had evolved from a lower to a higher state and had developed through the ages into different and progressively more perfect forms. He definitely dismissed the thought that one species could develop into another, and thereby denied the theory of the origin of species that has constituted the nucleus of the philosophy of evolution that originated with Darwin. Still less did he concur with the materialistic approach to life that was often expressed by Darwin’s followers, for nature, to him, was a harmonious whole, the development of which had been planned from the beginning and had been directed by an omnipotent and omniscient Creator.

As have those of most other taxonomists, many of Agardh’s concepts have become obsolete, especially the more general ones. For his descriptions of species, he had only pressed and dried material in herbaria; thus, his ideas about species have often had to be revised. He introduced many new ideas to algology, however, and was active in developing an increasingly keener systematic and morphological approach. His algae collection, which had been started by his father, was given to the University of Lund, where Agardh had been active as a teacher since 1834 and professor of botany from 1854 to 1879. The collection is one of the most varied in the world and contains many type specimens—an indication of the importance of his work.

BIBLIOGRAPHY

I. Original Works. Complete bibliographies of Agardh’s writings are in J. Ericksson, “Jacob Georg Agardh,” in Levnadsteckningar över Kungliga Svenska Vetenskapsakademiens ledamöter, V, pt. 2 (Stockholm, 1915–1920); and N. Svedelius, in Svenskt biografiskt lexikon, I (Stockholm, 1917–1918), 268–274. Among his works are Algae maris Mediterranei et Adriatici (Paris, 1842); Species, genera et ordines algarum, 6 vols. (Lund, 1848–1901); and Theoria systematis plantarum (Lund, 1858). Most of his letters and MSS are in the library of the University of Lund.

II. Secondary Literature. Writings on Agardh are the articles of Ericksson and Svedelius cited above and G. B. de Toni, “G. G. Agardh e la sua opera scientifica,” in La nuova notarisia, 17 (1902). 1–28.

Gunnar Eriksson