Some cases of partial reversion may be interpreted in the same way. Among the garden anemones, _Anemone coronaria_, there is a variety called the "Bride," on account of its pure white dowers. It is for sale with single and with double flowers, and these two forms are known to sport into one another, although they are multiplied in the vegetative way. Such cases are known to be of quite ordinary occurrence. Of course such sports must be considered as partial, and the same stem may bear both types of flowers. It even happens that some particular flower is partly double and partly single. Mr. Krelage, of Haarlem, had the kindness to [511] send me such a curious flower. One half of it was completely double, while the other half was entirely single, bearing normal and fertile stamens in the ordinary number. The same halfway doubling is recorded to occur among composites sometimes, and from the same source I possess in my collection a head of _Pyrethrum roseum_, bearing on half of its disk elongated corolla tubes, and on the other half the small disk-florets of the typical species. It is a current belief, that varieties are improved by continued culture. I have never been able to ascertain the grounds on which this conviction rests. It may be referred either to the purity of the race or to the complete development of the varietal character. In the first case it is a question of hybrid mixtures from which many young varieties must be freed before being placed on the market. But as we have already seen in a former lecture, this requires only three or four years, and afterwards the degree of purity is kept up to the point which proves to be the most suitable for practical purposes. The complete development of the varietal character is a question restricted to ever-sporting varieties, since in white flowers and other constant varieties this degree is variable in a very small and unimportant measure. [512] Hence the double flowers seem to afford a very good example for this discussion. It can be decided by two facts. First by a consideration of the oldest double varieties, and secondly by that of the very youngest. Are the older ones now in a better condition than at the outset? Have they really been gradually improved during the centuries of their existence? Obviously this can only be answered by a comparison of the figures given by older writers, with the varieties as they are now in culture. Munting's drawings and descriptions are now nearly two centuries and a half old, but I do not find any real difference between his double varieties and their present representatives. So it is in other cases in which improvements by crossing or the introduction of new forms does not vitiate the evidence. Double varieties, as a rule, are exactly the same now, as they were at the time of their first introduction.