Despite the subjects she studied at university, Lourteig's career was as a botanist, particularly as a taxonomist of the
Lythraceae,
Ranunculaceae,
Mayacaceae and
Oxalidaceae. Her interests extended to the history of botany in South America and the Antilles. In 1955 she was recruited by the
French National Centre for Scientific Research so moved to join the
National Museum of Natural History, France as curator of the New World botanic collection. She contributed to the supplement of the
Flore de France by
Hippolyte Coste and revisions of the
International Code of Botanical Nomenclature. She organised collections made by Aimé
Bonpland (1773-1858), José Celestino
Mutis (1732-1808), Surian and
Charles Plumier (1646-1704) that were in the Paris museum. She became a research associate at the museum in 1979. Lourteig collected plant materials in South America and also collected in the French Antarctic in 1963-1964 and 1969. She was editor of the journal
Lilloa. ==Publications==