The lopeared breed is the oldest English variety, and has been cultivated carefully since about 1785, the aim of the breeder being directed to the development of the size of the ears, and with such success that they sometimes measure more than 23 in.
All the well-known breeds of dogs are highly artificial and their maintenance requires the constant care of the breeder in mating, and in rejecting aberrant progeny.
As the breeder selects a congenital variation which suits his requirements, and by breeding from the animals (or plants) exhibiting that variation obtains a new breed specially characterized by that variation, so in nature is there a selection amongst all the congenital variations of each generation of a species.
Judged by the florists' rules, they are either good or bad in form, and pure or stained (white or yellow) at the base; the badly formed and stained flowers are thrown away, while the good and pure are grown on, these being known as "breeder" tulips.
The breeder bulbs and their offsets may grow on for years producing only self-coloured flowers, but after a time, which is varied and indefinite, some of the progeny "break," that is, produce flowers with the variegation which is so much prized.