Cultigens and Cultivars
Cultigen and cultivar may be confused with one another. Cultigen is a general-purpose term encompassing not only plants with cultivar names but others as well (see introductory text above), while cultivar is a formal classification category (in the ICNCP).
Although in his 1923 paper Bailey used only the rank of species for the cultigen, it was clear to him that many domesticated plants were more like botanical varieties than species and so he established a new classification category for these, the cultivar, generally assumed to be a contraction of the words “cultivated” and “variety”. Bailey was never explicit about the etymology of the word cultivar and it has been suggested that it is a contraction of the words “cultigen” and “variety” which seems more appropriate. He defined cultivar in his 1923 paper as:
... " a race subordinate to species, that has originated and persisted under cultivation; it is not necessarily, however, referable to a recognised botanical species. It is essentially the equivalent of the botanical variety except in respect to its origin ".
This definition and understanding of cultivar has changed over time (see current definition in cultivar).
Read more about this topic: Cultigen