August 7, 2021
The word cultivar was invented in the early 20th century when botanists raised the need to separate wild plant species from plants that were being cultivated with traits that were more popular with farmers and home gardeners.
Liberty Hyde Bailey (1858 - 1954) was an American horticulturist and botanist who cofounded the American Society for Horticultural Science. Bailey created the word cultivar in 1923 when he wrote:
"The cultigen is a species, or its equivalent, that has appeared under domestication". I now propose another name, cultivar, for a botanical variety ...that has originated under cultivation; it is not necessarily, however, referable to a recognized botanical species. It is essentially the equivalent of the botanical variety except in respect to its origin."1
A few examples of rose cultivars include such plants as 'Angel Face', 'Knock-Out', and 'Don Juan'. Some of the currently popular tomato cultivars are 'Better Boy', 'Cherokee Purple', and 'Super Sweet 100's'.
1. Bailey, Liberty Hyde (1923). "Various cultigens, and transfers in nomenclature". Gentes Herbarum. 1 (Part 3): 113-136. Wikipedia.