Engler, Heinrich Gustav Adolf
ENGLER, HEINRICH GUSTAV ADOLF
(b. Sagan, Silesia. Germany [now Zagań, Poland], 25 March 1844; d. Berlin-Dahlem, Germany, 10 October 1930)
Engler was the son of August Engler, a merchant, and Pauline Scholtz. At an early age his mother took him to Breslau, Germany (now Wroclaw, Poland), where he completed a classical education at the Magdalenen Gymnasium. During his years at the Gymnasium, he accompanied Rudolf von Uechtritz on botanical field trips. Engler later worked on the difficult and variable genus Saxifraga for his dissertation, for which he obtained a doctorate under Goeppert at the University of Breslau. After some years of teaching at Breslau, Engler became curator of the botanical collections at the Botanische Staatsanstalt in Munich, then under the supervision of Naegeli. Under the latter’s critical guidance, Engler reached maturity in his systematic work. After completing his monograph on Saxifraga, he began work on the tropical families Olacaceae, Icacinaceae, and the especially difficult Araceae for Martius and Ei-chler’s international team effort, the Flora Brasiliensis (1840-1906). With these wider studies Engler developed the systematic theory and methodology with which he would influence and dominate almost a half-century of plant taxonomy: a basically comparative morphological method was supplemented with elements from phytogeography, anatomy, embryology, and even —although more modestly —from phytochemistry. While conducting these studies Engler came to accept the Darwinian ideas on evolution as a background explanation of organic diversity. In 1878 he was offered the chair of systematic botany at the small (250 students) University of Kiel. Engler enthusiastically accepted this chance to pursue a university career, although he was not particularly gifted either as a teacher or an orator. His very light teaching duties left him ample time to develop his original ideas as well as his organizational skill. In 1880 he founded the Botanische Jahrbücher fur Systema-tikt Pflanzengeschichte und Pflanzengeographie, of which he edited and published sixty-two volumes in the course of nearly fifty years. For most of that period Engler’s Jahrbucher, as it was usually called, was the world’s foremost journal of plant systematics and phytogeography.
While at Kiel, Engler wrote Versuch einer Ent-wicklungsgeschichte der Pflanzenwelt… (1879-1882), which brought him widespread fame. Essentially, the book is the first attempt at a genetic and historical theory of the origin of the floristic diversity of the Northern Hemisphere. Engler proved that during the Tertiary period there existed in this hemisphere a somewhat homogeneous flora, which, modified by later glaciation, resulted in the present diversity of the floras of Europe, Eastern Asia, and Pacific and Atlantic North America.
In 1884 Engler was recalled to the University of Breslau to succeed Goeppert as professor of systematic botany and director of the botanical garden. His colleague from earlier Breslau days. Ferdinand Julius Cohn, was in charge of physiological botany; and it was Cohn who was mainly responsible for Engler’s remarkably broad interest in botany, comprising the cryptogams and also the higher plants. The Breslau period was significant because of Engler’s idea of producing an encyclopedia of the descriptive plant sciences. With Karl A. E. Prantl from Aschaffenburg, who was primarily in charge of the cryptogams and who died in 1893 in the early stages of the work, Engler began Die natürlichen Pflanzenfamilien, which was to become the last complete systematic and monographic survey of the plant kingdom from the generic level up to the present day. Between March 1887 and September 1915, 248 installments appeared, written by numerous collaborators. The basis of all treatments was clearly provided by Engler, who published several versions of his’Principien der systematischen Anordnung “in various volumes of the Pflanzenfamilien and also in the nine editions of his highly successful one-volume abridgment, Syllabus der Pflanzenfamilien.
Realizing that the theory of evolution provided the background for an understanding of organic diversity, Engler stressed that in actual practice there were insufficient historical and experimental data for a fully justified phylogenetic arrangement. Believing that it would be wrong to assume per se a monophyletic origin of plant life, he pointed out that parallel developments must have taken place at different times and places. Therefore, the actual basis for the system elaborated in the Pflanzenfalmilien remained that outlined during his years at Munich: morphology, phytogeography, and related subdisciplines had to provide the basic data for what would remain a subjective assessment of formal or genetic relationships. Premature evolutionary speculations had to be avoided. First, priority had to be given to the assembling of basic data. The Darwinian and Mendelian ideas on the origin of diversity, however, should never be lost sight of when trying to explain diversity. The Engler system of plant classification came to its full development in the Pflanzenfamilien and the Syllabus. Essentially the system recognized, contrary to earlier systems, the great diversity of what has so far been called” cryptogams, “and attributed high and equal rank to the various groups of algae, fungi, mosses, and ferns. The phanerogams, called Embryophyta siphonogama, were on an equal footing with twelve divisions of former cryptogams. The arrangement of the flowering plants still put the more highly specialized monocotyledons before the dicotyledons, which were later shown to contain all ancestral forms. Nevertheless, Engler’s system remained for many years the most widely accepted classification of all plants.
Through his many publications and clearly stated theoretical assumptions Engler had already won worldwide fame by 1889, when he was chosen to succeed Eichler as professor of botany and director of the botanical garden at Berlin. It was there that his great organizational gifts found their scope in the Second Reich environment of economic and colonial as well as cultural and scientific expansion. In the large new botanical garden, which was set up and developed between 1895 and 1910 in nearby Dahlem, Engler was able to illustrate his ideas on phytogeography. To continue the expansion of his nd ideas, a botanical museum and a staff of collaborators were at his disposal. The cryptogamic volumes of the Pflanzenfamilien began to appear, and material from Africa directed research on phanerogams increasingly toward the tropical regions of this continent.
During his Berlin period Engler produced his most important publication as sole author, the various volumes of Die Pflanzenwelt Afrikas. This work was part of a series of volumes on the main phytogeographic regions of the world: Die Vegetation der Erde. Engler also started a monographic survey of the plant world down to the species level, Das Pflanzenreich. After his retirement in 1921, he started a second edition of his Natürlichen Pflanzenfamilien.
As a scientist and organizer Engler dominated the Engler-Zeit, an entire era in systematic botany, in which the descriptive activities in the discipline reached an all-time high.
A complete list of Engler’s publications is in Ludwig Diels,” Zum Gedachtnis von Adolf Engler, “in Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie, 64 (1931), i-lvi.
Engler’s works include De genere Saxifraga (Halle, 1866); Monographie der Gattung Saxifraga (Breslau, 1872); Versuch einer Entwicklungsgeschichte der extratropischen Florengebiete der nordlichen Hemisphare (Leipzig, 1879-1882); Versuch einer Entwicklungsgeschichte der Pflanzenwelt insbesondere der Florengebiete, seit der Tertiärperiode, 2vols. (Leipzig, 1879-1882); Die naturlichen pflanzenfamilion (Leipzig, 1887-1915; 2nd ed., Leipzig, 1924-1960), written with karl A.E. prantl, as editer and contributor; syllabus der vorlesungen über specielle und medicinisch-phar-maceutische Botanik (Berlin 1892; 9th ed., 1924); Die Pflanzenwelt Ost-Afrikas (Berlin, 1895); Das Pflanzenreich (Berlin, 1900-1953), as editor and contributor; and Die Pflanzenwelt Afrikas (Leipzig, 1910-1915), which is pt. 9 of his Die Vegetation der Erde. 15 vols. (Leipzig, 1896-1923), written with O. Drude.
No formal biography of Engler exists. Diels’s obituary, cited above, is the most complete and independent evaluation of Engler as a scientist; the many other published obituaries add little to the basic picture. For a review of secondary literature on Engler’s major publications, see F. A. Stafleu, Taxonomic Literature (Utrecht, 1967), 133-149.
Frans A. Stafleu