The Melchior system, "a reference in all taxonomic courses", is a classification system detailing the taxonomic system of the Angiospermae according to A. Engler's Syllabus der Pflanzenfamilien (1964), also known as "modified or updated" Engler system. The collaborators in orders (and some families) were the following:

subdivisio Angiospermae

classis Monocotyledoneae

ordo Helobiae

ordo Triuridales

ordo Liliiflorae

ordo Juncales

ordo Bromeliales

ordo Commelinales

ordo Graminales

ordo Principes

ordo Synanthae

ordo Spathiflorae

ordo Pandanales

ordo Cyperales

ordo Scitamineae

ordo Microspermae

classis Dicotyledoneae

subclassis Archychlamydeae

ordo Casuarinales

ordo Juglandales

ordo Balanopales

ordo Leitneriales

ordo Salicales

ordo Fagales

ordo Urticales

ordo Proteales

ordo Santalales

ordo Balanophorales

ordo Medusandrales

ordo Polygonales

ordo Centrospermae

ordo Cactales

ordo Magnoliales

ordo Ranunculales

ordo Piperales

ordo Aristolochiales

ordo Guttiferales

ordo Sarraceniales

ordo Papaverales

ordo Batales

ordo Rosales

ordo Hydrostachyales

ordo Podostemales

ordo Geraniales

ordo Rutales

ordo Sapindales

ordo Julianiales

ordo Celastrales

ordo Rhamnales

ordo Malvales

ordo Thymelaeales

Note: Sonderothamnus R.Dahlgren, 1968 is posterior to the publication of this work, and Stylapterus A.Juss. was included by G. Bentham & J.D. Hooker in Penaea. Note: the classification of Thymelaeaceae was based on Domke 1934.

ordo Violales

ordo Cucurbitales

ordo Myrtiflorae

ordo Umbelliflorae

subclassis Sympetalae

ordo Diapensiales

ordo Ericales

ordo Primulales

ordo Plumbaginales

ordo Ebenales

ordo Oleales

ordo Gentianales

ordo Tubiflorae

ordo Plantaginales

ordo Dipsacales

ordo Campanulales