Barthélemy Charles Joseph Dumortier (French: [baʁtelemi ʃaʁl ʒozɛf dymɔʁtje]; 3 April 1797 – 9 July 1878) was a Belgian who conducted a parallel career of botanist and Member of Parliament and is the first discoverer of biological cell division.

In 1832, he described cell division in simple aquatic plants (French 'conferve'):[4] “Le développement des conferves est aussi simple que leur structure; il s’opère par l’addition de nouvelles cellules aux anciennes, et cette addition se fait toujours par l’extrémité.

La cellule terminale s’allonge plus que celles inférieures; alors il s’opère dans le fluide intérieur une production médiane, qui tend à diviser la cellule en deux parties dont l’inférieure reste stationnaire, tandis que la terminale s’allonge de nouveau, produit encore une nouvelle cloison intérieure, et ainsi de même.

Voilà ce qu’il est impossible de déterminer; mais toujours est-il vrai de dire que plus tard elle paraît double dans les conjuguées, et que quand deux cellules se séparent naturellement, chacune d'elles est close aux deux extrémités.” In the analogous English translation: “The development of the conferve is as simple as its structure; it takes place by the attachment of new cells to the old, and this attachment always takes place from the end.

It is impossible to determine this, but it is always true that it later appears double when united, and that when two cells naturally separate, each of them is closed at both ends.” In 1872 he was awarded the honorary title of Minister of State.

In 1829 Dumortier was already regarded as one of the greatest naturalists of the Low-Countries and became a member of the Académie de Bruxelles.

[5] His reputation as a botanist was so brilliant that the Home Office asked him to be its representative in the Brussels’ Botanic Garden, then a joint stock company, supported by the State.

He succeeded in convincing the Parliament in 1869 of buying the impressive herbarium and dried collections of the late Carl Friedrich Philipp von Martius.