Sanio, Karl Gustav

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(b. Lyck, East Prussia [now Elk, Poland], 5 December 1832; d. Lyck, 28 January 1891)


The son of Johann Sanio, a landowner, Sanio began studying the flora and fauna around Lyck while attending the Gymnasium. After passing the final secondary school examination in 1852, he studied science and medicine at the University of Königsberg, where he earned the Ph.D. for the dissertation “Florula Lyccensis” in 1858. In the same year Sanio qualified as lecturer in botany with an essay entitled “Untersuchungen über die Epidermis und die Spaltöffnugen der Equisetaceen.” The university administration objected to his manner of living, however, and he was ultimately compelled to give up teaching. He returned to his family in Lyck, where he conducted botanical research for the rest of his life.

Although Sanio’s floristic examination of the region around Lyck essentially ended with his dissertation, he occasionally returned to floristics and systematics. He was mainly concerned, however, with other areas of botany, including the ferns, the Characae, and, above all, the moss genus Drepanocladus (Harpidium).

Sanio had begun microscopic studies of plant anatomy as a student, and his first publication was on the development of the spores of Equisetum. He recognized that the spiral bands (haptera) arise in the outer layer of the spore wall and exhibit an oblique structure on the exterior. Sanio was the first to point out that the stomata of Equisetum are composed of two pairs of cells: an external, upper pair and an inner, lower one with thickening stripes. The upper pair lies either at the same level as the epidermis or deeper. On the basis of this finding, Julius Milde later (1865) divided the genus Equisetum into two groups of species, Equiseta phaneropora and Equiseta cryptopora.

Sanio made his most important contributions in the anatomy of wood, a subject that had attracted his attention when he was a student. In his first studies on this topic, he dealt with the wood parenchyma, which is found in almost all woody plants. He found that it consists of rows of cells that are joined into a spindle-shaped unit and that arise from a fiber cell through oblique division. In autumn the wood parenchyma contains starch, which is dissolved in the spring.

Sanio explained the structure and development of cork so completely that later writers could add nothing essential to his account. He showed that every radial row of cork cells is derived from the action of a single cambium cell, which divides only centripetally or carries out one or two divisions in a centrifugal direction and then divides uninterruptedly only in a centripetal sequence. In the first case only cork is produced; in the second, a thin phelloderm is generated on the inside at the start of the process. The formation of cork occurs either in the epidermis or in the uppermost cortical layers, rarely in deeper tissue.

Sanio thoroughly examined 166 European and exotic trees and shrubs. Though this research he resolved many uncertainties concerning the terminology and origin of various types of cells. He also explained the formation of annual rings and established the first table for identifying woods on the basis of anatomical features (1863).

Sanio’s last works were devoted to the anatomy of the wood of the Scotch pine (Pinus silvestris). he showed that the cells of the wood (tracheids) in trunks and branches grow in length and breadth from the inside toward the outside for a number of annual rings, until a final size is reached. Sanio refuted Hartig’s view that every radial row of wood and phloem cells derives from two mother cells, one of which transmits only wood cells toward the inside, while the other yields only phloem cells that move toward the outside. He demonstrated that each radial wood and phloem cell row in the cambium derives from only a single mother cell, which alternately sends wood cells toward the inside and phloem cells toward the outside.

Sanio owed the success of his scientific works to outstanding skill in preparing anatomical thin sections (with a razor he could produce series of sections of.03 mm) and to his great care in observation and drawing. His work also benefited from his critical attitude toward the literature and from examination of the greatest possible number of genera and families, which prevented hasty conclusions based on a few samples.

Sanio’s findings and his precise terminology became widely known through their inclusion in H. A. de Bary’s Vergleichende Anatomie der Vegetationsorgane der Phanerogamen und Farne (1877). Almost all the terms that he coined are still in use.


I. Original Works. Sanio’s writings include “Über die Entwickelung der Sporen von Equisetum,” in Botanische Zeitung, 14 (1856), 175–185, 193–200: “Unter-suchungen über diejenigen Zellen des Holzkörpers, welche im Winter assimilierte Stoffe f¨hren,” in Linnaea, 29 (1857), 111–168; “Florula Lyccensis,” ibid., 169–264; “Untersuchungen über die Epidermis und die Spaltöffnungen der Equisetaceen,” ibid., 385–416; “Vergleichende Untersuchungen über den Bau und die Entwickelung des Korkes,” in Jahrbücher für wissen-schaftliche Botanik, 2 (1860), 39–108: “Vergleichende Untersuchungen über die Elementarorgane des Holz-körpers,” in Botanische Zeitung, 21 (1863), 85–91, 93–98, 101–111, 113–118, 121–128: “Vergleichende Untersuchungen über die Zusammensetzung des Holzküorpers,” ibid., 357–363, 369–375, 377–385, 389–399, 401–412: “Uber die Grösse der Holzzellen bei der gemeinen Kiefer (Pinus silvestris),” in Jahrbücher für wissenschaftliche Botanik, 8 (1872), 401–420: and “Anatomie der gemeinen Kiefer (Pinus silvestris),” ibid., 9 (1873), 50–126.

II. Secondary Literature. A detailed obituary is by P . Ascherson, in Verhandlungen des Botanischen Vereins der Provinz Brandenburg, 34 (1893), xli–xlix. Shorter biographies are J. T. Ratzeburg, Forstwissen-schaftliches Schriftsteller-Lexikon (Berlin, 1872), 449–450; and Allgemeine deutsche Biographie, LIII (1907), 709–711. Sanio’s work is discussed in H. A. de Bary, Vergleichende Anatomie der Vegetationsorgane der Phanerogamen und Farne (Leipzig, 1877): K. Mägdefrau, Geschichte der Botanik (Stuttgart, 1973); Julius Sachs, Geschichte der Botanik (Munich, 1875): and T. Schmucker and G. Linnemann, “Geschichte der Anatomie des Holzes,” in H. Freund, ed., Handbuch der Mikroskopie in der Technik, V, pt. 1 (Frankfurt, 1951), 1–78.

Karl MÄgdefrau