No. 388.] FOUR CATEGORIES OF SPECIES. 297 
features of our islands rather than with the number of farms 
or building lots into which they may be subdivided. 
The fourth type of species may not appear logically dis- 
tinct from the second and third, since natural hybrids occur, 
and have had, no doubt, their influence in evolution. From the 
practical standpoint, however, it may be maintained that the 
hybrid nature of a new form is not to be assumed without 
reason; and it is plain, in addition, that where we know the 
history and ancestry of a hybrid or selective variety, we should 
draw every possible advantage from that knowledge instead of 
undertaking the gratuitous labor of attempting a second and 
entirely artificial diagnosis. With domestic animals classifica- 
tion is carried to its ultimate extreme by means of carefully 
recorded pedigrees, while in the cultivated plants a similar 
refinement exists, particularly in the varieties of fruits which are 
propagated by grafting, the so-called variety being, in a sense, 
but a single individual, in spite of its extensive multiplication 
and distribution. Such classifications are not less scientific 
because they are also of practical utility, and the necessity 
of uniformity in the nomenclature of artificial varieties and 
hybrids is becoming a scientific as well as a popular necessity. 
At the same time it is extremely doubtful whether the desul- 
tory systematic methods of the past and present can supply 
such adesideratum. Any attempt at instituting an authoritative 
nomenclature of cultivated plants would need, in justice to the 
practical interests concerned, to be so equipped as to furnish 
prompt and accurate determinations, and to be able to incor- 
porate into knowledge and provide names for all new varieties 
without loss of time. Such a plan once carried into execution 
would. be of the greatest importance to agriculture, since it 
would render practicable the execution of laws which might be 
enacted to prevent the present enormous losses from falsely 
named and dishonestly advertised seeds and propagating 
stock, 
