Some interesting reading of late. It appears that a cultivar may be propagated sexually or asexually.
Cultivars may be produced from seed and therefore may exhibit some variation in traits other than that for which the selection was made. For example, Lavandula angustifolia ‘Munstead Dwarf’ is a lavender selected for its dwarf habit. Even if seed grown, all plants so named should not exceed 18 inches in height, but may show slight variation in flower or foliage colour, habit, etc.
In order for all Munstead cultivars to be identical, or clones, they would have to be propagated asexually from cuttings. Many people do not realize that ‘cultivar‘ is not synonymous with ‘clone.’