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Now the fertility of first crosses, and of the hybrids produced from them, is largely governed by their systematic affinity. This is clearly shown by hybrids never having been raised between species ranked by systematists in distinct families; and on the other hand, by very closely allied species generally uniting with facility.
It should be remembered that systematists are far from pleased at finding variability in important characters, and that there are not many men who will laboriously examine internal and important organs, and compare them in many specimens of the same species.
As the presence of rudimentary organs is thus due to the tendency in every part of the organisation, which has long existed, to be inherited we can understand, on the genealogical view of classification, how it is that systematists have found rudimentary parts as useful as, or even sometimes more useful than, parts of high physiological importance.
Because, with the many thousands of students of natural science all over the world, each anxious to get into print as the discoverer of some new form, the systematists have a dead weight of names on their hands that by a rational and enlightened revision could doubtless be reduced to but a fraction of their present disheartening array.
These terms, extensively used by systematists, only refer, however, to the grosser features of the seed, and indicate the more or less evident occurrence of a food-reserve; many so-called exalbuminous seeds show to microscopic examination a distinct endosperm which may have other than a nutritive function.
On the other hand it seems to be rich in elementary species, but an adequate study of them has as yet not been made. Unfortunately many of the better systematists are in the habit of throwing all these interesting forms together, and of omitting their descriptive study. I have made a large number of crosses between such undescribed types and as a rule got constant hybrid races.
Recalling the results of the last lecture, we see that the species of the systematists are not in reality units, though in the ordinary course of floristic studies they may, as a rule, seem to be so. In some cases representatives of the same species from different countries or regions, when compared with one another do not exactly agree.
This is as wrong as it is gratuitous. The "popular" book, delightful as it may be, could not have been written, or, if written, would have had little real value, had it not been for the help obtained from the systematists, who, with almost infinite toil, have made possible the scientific classification of the numerous members of the bird tribe.
His reply was that, as usual, they had been singing with splendid effect on almost every day after the middle of February. What is the reason of this difference between the eastern and western birds? They are, according to the systematists, the same type, and yet they behave so differently. The solution of the problem is, after all, quite simple.
More than fifty different sorts of the coconut are described from the Indian shores and islands, with distinct local and botanical names. Miquel, who was one of the best systematists of tropical plants, of the last century, described a large number of them, and since, more have been added. Nearly all useful qualities vary in a higher or lesser degree in the different varieties.
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