In 1894 Ferdinand Pax, one of the most productive collaborators in the Engler German school, publishes 12 new African species of "Acalypha". Pax, and the German botanist Käte Hoffmann, were entrusted with preparing the genus for the enormous "Das Pflanzenreich", where all species known in the world so far are gathered and ordered (Pax & Hoffmann, 1924). They deem ca. 390 species as valid ones, of which 81 are first time described. Such a work is considered, even now, as the most complete revision of genus worldwide, and the necessary reference point for any taxonomic or local flora study. The infrageneric classification presented by Pax & Hoffmann is based on that from Müller Argoviensis, except in the rank of subgeneric taxa. Moreover, they use series and section categories in an opposite way to Muller’s: the series are described as higher ranked than sections are. So they divide "Acalypha" into three subgenera: "Linostachys", "Androcephala" and "Euacalypha". The subgenus "Androcephala", single-typed, includes a species from Madagascar with pedicellate female flowers and capituliform male inflorescences. They divide subgenus "Linostachys" into three sections, and subgenus "Euacalypha" into 8 series and 39 sections. Pax & Hoffmann consider as “sections” the lower category groups, which Müller designates by the symbol §. According to Grady Webster (1967), such “sections” from Pax & Hoffmann are comparable to subsections or series in other "Euphorbiaceae" genera. The last input on "Acalypha" from Pax & Hoffmann is published in "Die Natürlichen Pflanzenfamilien" by Engler & Prantl (Pax & Hoffmann 1931). It is just a synthesis of the treatment given in "Das Pflanzenreich", where all species are classified and listed without any description or key.