One of the prime systems of plant taxonomy, the Engler system was devised by Adolf Engler (1844–1930), and is featured in two major taxonomic texts he authored or co-authored. His influence is reflected in the use of the terms "Engler School" and "Engler Era". Engler's starting point was that of Eichler who had been the first to use phylogenetic principles, although Engler himself did not think that he was.[clarification needed] 
His modified Eichler schema first appeared in 1886 in his Guide to Breslau Botanic Garden (of which he was the director) and was expanded in his Syllabus der Pflanzenfamilien in 1892. This reflected the new post-Darwinian perspective. Engler's Syllabus first appeared in 1892 with the title Syllabus der Vorlesungen über specielle und medicinisch-pharmaceutische Botanik. Many subsequent editions have appeared since, and it was continued after Engler's death in 1930. The most recent edition was the 13th in 2009.
The other major work was Die Natürlichen Pflanzenfamilien (1887-1915) written with Karl Anton Prantl in 23 volumes. An incomplete second edition was issued in 28 parts (1924-1980). Die Natürlichen Pflanzenfamilien consisted of a complete revision of plant families down to generic level and often even further. Die Natürlichen Pflanzenfamilien is still considered one of the few true World Floras. Finally there was the also incomplete Das Pflanzenreich (1900–1968), a multi-authored work which attempted to provide a modern version of Linnaeus' Species Plantarum (1753). The Engler system rapidly became the most widely used system in the world.
References to the Engler system may imply an edition of the Syllabus der Pflanzenfamilien or Die Natürlichen Pflanzenfamilien. The different approaches between the two works and the different editions has resulted in inconsistencies in the descriptions of the system. A number of references to the Engler system actually refer to later revisions ('modified Engler system') undertaken by Melchior and colleagues, the 12th edition of the Syllabus (1964). Many of the world's herbaria have been organised on the Engler system, particularly in North America and in Europe other than Britain. The Engler system is also reflected in his multi-volume collaborative work, begun in 1900, Das Pflanzenreich: regni vegetablilis conspectus.
Plants were considered to form a number of divisions (Abteilung), the number of which continually changed but initially (1886) was four and in 1919 was thirteen. Many of these referred to lower life forms such as bacteria and algae that would not necessarily be considered as plants today. Initially higher plants (Embryophyta or terrestrial plants) were considered in two divisions, Embryophyta Asiphonogama (bryophytes, pteridophytes) and Embryophyta Siphonogama (Spermatophytes: gymnosperms, angiosperms), but were later subdivided. Embryophyta Siphonogama replaced the older term Phanerogamae, and the classes were further divided into groups of families, called orders. Engler followed Eichler's phylogeny, placing the monocotyledons before the dicotyledons, and within the latter the Archichlamydeae before the Metachlamydeae. While the groupings were largely based on those of Bentham and Hooker, the ordering was very much based on the concept of the primitive plant and those that were derived from these.
Main article: Die Natürlichen Pflanzenfamilien
Synopsis of first edition 
Main article: Syllabus der Pflanzenfamilien
Synopsis of first edition 
In the foreword included in the first part of this monumental work, Engler explained the need for a more detailed monograph than in Pflanzenfamilien.