Svedelius, Nils Eberhard
SVEDELIUS, NILS EBERHARD
(b. Stockholm, Sweden, 5 August 1873; d. Uppsala, Sweden, 2 August 1960)
phycology.
Svedelius’ father, Carl, was a Supreme Court justice; and his father’s family included numerous intellectuals, clergymen, governmental officials, army officers, scholars, and teachers. His mother, Ebba Katarina Skytte of Sätra, belonged to the untitled nobility. At a young age he showed keen interest in botany; and in 1891 he entered the University of Uppsala, where F. R. Kjellman was one of his teachers. The marine algal flora of high latitudes was a main interest of Kjellman, who had been the botanist of the Vega expedition, which in 1878–1880 accomplished the Northeast Passage. In Sweden the marine algae had been studied mainly at the North Sea coast, whereas the depauperated flora of the Baltic Sea had been neglected. Svedelius therefore selected as the topic for his doctoral dissertation the algal flora of the southern Baltic coast of Sweden, with special emphasis on their morphological and ecological responses to the decreased salinity. In 1901 he received the doctorate and became a docent the following year. Svedelius was appointed professor of botany in 1914 and retired in 1938. Although he retained a lifelong interest in the algae of the Baltic, Svedelius made his contributions of fundamental importance in a totally different branch of phycology-in the elucidation of the various life cycles in the red algae (Florideae) and their evolutionary value.
In 1902–1903 Svedelius visited the tropics, spending most of his time in Ceylon, particularly at Galle, which has a large coral reef where he surveyed the marine algae and their taxonomy, ecology, and distribution. Rather little was ever published from this journey; but it focused his interest on the red algae, and his experiences in Ceylon were in many ways valuable to his later investigations.
The introduction of the microtome and fixing and staining techniques at that time opened a new era in biology. The alternation between a gametophytic and a sporophytic generation had long been known in ferns and mosses, as had the existence of different kinds of reproductive bodies in algae; but no regular pattern could be discerned in the latter group. In 1904 J. L. Williams established the alternation between two externally similar generations in a brown alga, and two years later S. Yamanouchi found it in a red alga, the formation of tetraspores being preceded by meiosis. Realizing that the technical means were now at hand, Svedelius decided to investigate reproduction in the red algae. After establishing one more case of regular alternation, he turned to Nitophyllum punctatum (1914), in which tetraspores were known to occur both on special (sporophytic) and on gametophytic individuals. The latter were, as expected, haploid. Their apparent tetraspores were formed without meiosis and thus were not true tetraspores, but a kind of accessory spore. In 1915 Svedelius showed that Scinaia furcellata, a species without tetraspores, does not possess independent alternating generations because the first nuclear division after fertilization is meiotic and the carpospores thus become haploid. For the rest of his life (his last paper was written in 1955) he continued along these lines, studying additional species, finding new complications and modifications in the life cycles, and trying to trace their phylogenetic connections. All his publications are exhaustive, detailed, exact, and profusely illustrated by his own instructive and beautiful drawings.
From the beginning of his life-cycle studies Svedelius was interested in the general significance of the alternation of generations in the plant kingdom and was perhaps the first to point out that the acquisition of a sporophyte must be of immense evolutionary value: in organisms in which the zygote is the only diploid cell, one fertilization is followed by only one meiosis, whereas in organisms with a full diploid generation, one fertilization is followed by numerous meioses, each with its own possibilities of genetic segregations.
Svedelius was not exclusively a phycologist . He also published papers on floral biology and on seed anatomy. His inherent interest in organization, administration, and economics engaged him deeply in the affairs of his university and of several academies and learned societies . In 1935-1950 he was president of the Botanical Section of the International Biological Union .
BIBLIOGRAPHY
I. Original Works. Svedelius’ writings include Studier öfver Österjöns hafsalgflora (“Studies of the Marine Algae of the Baltic Sea”. Uppsala, 1901), his dissertation: “Ueber den Generationswechsel bei Delesseria Sanguinea,” in Svensk botanisk tidskrift, 5 (1911), 260–324:“Ueber die Tetradenteilung in den vielkernigen Tetrasporangiumanlagen bei Nitophyllum punctatum,” in Berichte der Deutschen botanischen Gesellschaft, 32 (1914), 48–57; “Ueber Sporen an Geschlechtspflanzen von Nitophyllum punctatum, ein Beitrag zur Frage des Generationswechsels der Florideen,” ibid., 106–116: “Zytologisch-entwickelungsgeschichtliche Studien über Scinaia furcellate. Ein Beitrag zur Frage der Reduktionsteilung der nicht tetrasporentragenden Florideen,” in Nova acta Regiae societatis scientiarum upsaliensis, 4th ser., 4 (1915), 1–55:“Generationsväxlingens biologiska betydelse” (“The Biological Significance of the Alternation of Generations”), in Svensk botanisk tidskrift, 12 (1918), 487–490: “Alternation of Generations in Relation to Reduction Division,” in Botanical Gazette, 83 (1927), 362–384: “The Apomictic Tetrad Division in Lomentaria rosea in Comparison With the Normal Development in Lomentaria clavellosa,” in Symbolae botanicae upsalienses,2 (1937),1–54;and“Zytologisch-entwickelungsgeschichtliche Studien über Galaxaura,eine diplobiontische Nemalionales-Gattung,” in Nova acta Regiae societatis scientiarum upsaliensis, 4th ser., 13 (1942), 1–154.
II. Secondary Literature. More detailed biographies are G. F. Papenfuss, “Nils Eberhard Svedelius, A Chapter in the History of Phycology,” in Phycologia, 1 , no. 4 (1961). 172–182, with a complete bibliography of his phycological papers: and C. Skottsberg, “Nils Eberhard Svedelius 1873–1960,” in Biographical Memoirs of Fellows of the Royal Society, 7 (1961), 295–312, with a complete bibliography of his works.
J. A. Nannfeldt