From Today in Science History:
Carl Erich Correns (Born 19 Sep 1864; died 14 Feb 1933). German botanist and geneticist who in 1900, independent of, but simultaneously with, the biologists Erich Tschermak von Seysenegg and Hugo de Vries, rediscovered Gregor Mendel’s historic paper outlining the principles of heredity. In attempting to ascertain the extent to which Mendel’s laws are valid, he undertook a classic study of non-Mendelian heredity in variegated plants, such as the four-o’clock (Mirabilis jalapa) which he established (1909) as the first conclusive example of extrachromosomal, or cytoplasmic, inheritance (cases in which certain characteristics of the progeny are determined by factors in the cytoplasm of the female sex cell).
Florentino Ameghino (Born 19 Sep 1853; died 6 Aug 1911). Argentine paleontologist and anthropologist who made significant contributions to the field of vertebrate paleontology and established the Pampas region of Argentina as a rich source of fossils. He discovered over 6,000 fossil species and classified 35 suborders of mammals. Ameghino’s controversial discoveries of stone implements, carved bones, and other signs of a human presence in Argentina during the Pliocene, Miocene, and earlier periods served to increase his worldwide fame.
David Starr Jordan (Died 19 Sep 1931; born 19 Jan 1851). American naturalist, educator, and the foremost American ichthyologist of his time. Jordan was a renowned expert in many fields. For example, he served as an expert witness on the validity of the theory of evolution at the Scopes trial in Tennessee. He was known for his work in education, philosophy, and as a peace activist. He often approached the subject of peace from a biological angle, arguing that war was detrimental to the health of the species because it removed the strongest individuals from the gene pool. Although he campaigned vigorously against US involvement in World War I, once war was declared, he advocated aggressive measures to end the conflict quickly.
Francis Darwin (Died 19 Sep 1925; born 16 Aug 1849). English botanist who was the third son of Charles Darwin, and published the results of his collaboration with his father in the publication of The Movement of Plants (1880).
Georg August Schweinfurth (Died 19 Sep 1925; born 29 Dec 1836). German botanist who travelled in the interior of East Africa (from 1868) and studied the inhabitants together with the flora and fauna of the region. During this journey, in Mar 1870, he discovered the River Welle (Uele), explored the upper Nile basin, and charted the western feeders of the White Nile. He wrote about the cannibalistic practices of the Mangbettu, and his discovery of the pygmy Akka confirmed the existence of dwarf races in tropical Africa (The Heart of Africa, 1873). During 1875-88, he lived in Cairo, where he founded the Royal Geographical Society of Egypt. He made historical, geological, ethnographical and botanical investigations ranging from there to the Arabian desert.
Giacomo Doria (Died 19 Sep 1913; born 1 Nov 1840). Italian naturalist and explorer who conducted important research in systematic zoology. Pursuing his work, he made expeditions to Persia (1862), Borneo (1865-66) and Tunisia (1879). In 1867, he founded the civic museum of natural history in Genoa. The collection he donated became the nucleus of the museum, which he directed for more than 40 years. He was also director of Societa Geografica Italiana (1891-1900). The museum he founded now contains important zoolological, paleontological, botanical, and mineralogical collections from all over the world. These collections are continually growing, now estimated to be more than 3.5 million exhibits.
Olof Swartz (Died 19 Sep 1818: born 21 Sep 1760). Swedish botanist who left a legacy of a collection of plants from his botanical tours of the West Indies, Jamaica, North America, Puerto Rico, Haiti and Cuba between 1783-87. On his return, he described nearly 900 species, most of them new, in Flora Indiae occidentalis (3 vols., 1797-1806). The Swedish Museum of Natural History now holds the collection, about 6000 specimens of phanerogams and ferns, mostly from the West Indies. It is a part of their Regnellian herbarium. He is also noted for his taxonomic studies of specific plant groups, including orchids, mosses and especially ferns. He also published Nova Genera et Species Plantarum seu Prodromus (1788) and Observationes botanicae (1791).