nary seedless varieties (such as bananas, navel oranges, and the tiny seedless grapes sold as dried "currants") only on the supposition that in the latter also there had been a loss of vigor through long-continued non-sexual propagation.
The agreeable tartness of the barberry fruit, which makes it so generally and so highly esteemed, is due to the presence of 
Fig. 20.—Berberis vulgaris. Vertical section of berry, showing two seeds, each containing copious reserve food and a long, well-developed embryo. malic acid, a substance found also in the foliage. Besides being made into preserves and jellies, the ripe fruit is candied or may be dried like raisins. While yet green the berries are sometimes pickled as a substitute for capers. Barberry preserve is, moreover, often used as the basis of a refreshing summer drink—a sort of "barberryade." Finally, it is reported that in our Western States the fruit of Berberis aquifolium and certain other native species is made to yield upon fermentation an agreeable wine.
But, for all their attractiveness to us, the berries seem to be less in favor with birds than are many fruits which we care nothing for. So long as the more succulent or less acid fruits are to be obtained, birds visit the barberry but little. When winter comes, however, they are glad enough to profit by the barberry's offer of something to eat, and the bright scarlet clusters do not dangle in vain.
Kerner fed certain thrushes with barberries, and found that the resistant seeds not only passed unharmed through the digestive tract, but their power of germination was improved, as shown by comparing them with seeds which had not been eaten. Add to this advantage the long distances which birds are likely to carry the seeds they eat, and the likelihood of their depositing them in most favorable situations, and it will at once be apparent how much superior to other methods is this mode of dissemination.
There can be little doubt that in the primitive ancestors of the barberry family the fruits were dry capsules which depended upon the wind to distribute their numerous seeds, as is the case to-day in the majority of herbaceous Berberidaceæ. That is to say, if we suppose the six pistils of the primitive berberidaceous flower (see Fig. 17) to have ripened into as many capsules, we shall have a form of fruit from which not improbably may have been derived all the different forms of fruit exhibited in modern representatives of the family. Confining our attention to the line which culminates in the barberry, it will be seen that the supposition of such a fruit's having descended from the primitive form above men-
