Adolf Engler, German botanist, was educated at the University of Breslau (now Wroclaw, Poland), where he gained his doctorate in 1866 with a thesis on the genus Saxifraga. He was a lecturer at the Magdalene-Gymnasium from 1866 to 1873, then private tutor and herbarium curator at Munich to 1877, and professor of botany at the University of Kiel from 1878 to 1883. Here he completed an important early work on plant geography and the historical development of the flora of the world, Versuch einer Entwicklungsgeschichte der Pflanzenwelt (2 vols, 1879-1882), founded his Botanische Jahrbucher für Systematik, Pflanzengeschichte und Pflanzengeographie in 1880, and edited it for the next 50 years. From 1884 to 1888 he was professor of botany at the University of Breslau. In the latter year he edited Plantae marlothianae, published in the Botanische Jahrbucher and based on the specimens collected by H.W. Rudolf Marloth* during several collecting trips in the Cape Colony and Namibia. With K.A.E. Prantl he edited an original, comprehensive encyclopaedia of the vegetable kingdom, Die natürlichen Pflanzenfamilien nebst ihren Gattungen..., published from 1887 to 1911. From 1889 to his retirement in 1921 he was professor of botany at the University of Berlin and director of the botanic gardens there. Under his energetic leadership the German colonies in Africa were botanically explored. As a result he wrote "Beigräge zur Flora von Afrika" (Botanische Jahrbucher..., 1892-1900, in 18 parts) and initiated several ambitious publications which he edited and to which he made significant contributions. These included Monographieen afrikanischer Pflanzen-Familien und -Gattungen (1898-1904), eight monographs of which he wrote No. 1 (1898) on the Moraceae, and, with L. Diels, No. 3 (1899) and No. 4 (1899) on the Combretaceae. His Die Pflanzenwelt Afrikas (5 vols, 1908-1925) dealt mainly with tropical Africa but included southern African plants. It formed one of a series of works on the geography of plants published, with O. Drude as co-editor, under the general title Die Vegetation der Erde (15 vols, 1896-). Another series of monographs he edited was published from 1902 onwards under the title Das Pflanzenreich. His Syllabus der Pflanzenfamilien: Eine Uebersicht über das gesammte Pflanzensystem, mit Berucksichtigung der Medicinal- und Nutzpflanzen... (Berlin, 1898) appeared in many later editions until 1954. Über die Hochsgebirgsflora des Tropischen Afrika (Berlin, 1892) is a comprehensive work that includes references to South African plants.
Engler first visited southern Africa in 1902, travelling from Cape Town to the Transvaal and then to Delagoa Bay (now Baia de Maputo) and on to East Africa. Upon his return to Germany he read a paper in January 1903, "Uber die Frühlingsflora des Tafelberges by Kapstadt", which was published the same year. His second visit was in 1905, as one of the eminent foreign visitors invited to attend the joint meeting of the British and South African Associations for the Advancement of Science. In Cape Town, on 17 August, he and several other delegates received honorary Doctor of Science (DSc) degrees at a special graduation ceremony of the University of the Cape of Good Hope. That same day he read a paper, "On the vegetation and the floral elements of tropical Africa", describing the flora of different climatic regions. A summary of the paper was published in the British Association's Report of the meeting. He also used the opportunity to climb Table Mountain with Marloth. Travelling with other delegates to Durban by boat he met John Medley Wood* at the Botanic gardens there. In the Transvaal he collected plants around Johannesburg, Pretoria, and along the Magaliesberg to Zeerust and Mafikeng, then going on to Zimbabwe and East Africa. His "Beiträge zur Kenntniss der Pflanzenformationen von Transvaal und Rhodesia", published in the Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften in 1906, describes his travels and botanising in southern Africa during this visit. In 1905 he also published a paper on the botanical relation between tropical Africa and America, and the assumption of a sunken continent between them. A few years later, in 1908 and 1909, he received parcels of duplicate plants from H.H.W. Pearson* at the South African Museum's herbarium. Returning for a third visit in 1913 he travelled through Namibia with Professor M.K. Dinter* during April, from Swakopmund to Tsumeb and south to Keetmanshoop, leaving the territory at Lüderitz.
Engler was an extremely productive botanist and wrote numerous papers and monographs in addition to those mentioned. He undertook many overseas expeditions and receicved a number of honorary doctorates. He developed a phylogenetic system according to which many modern herbaria are arranged, and emphasized the importance of geological factors on plant geography. He is commemorated in the genera Engleria, Englerella, and Englerastrum, as well as in many species names.