600 
Cultivated Plants of the Future. 
times finds its way among the materials used for cakes or for manu- 
factured cattle foods. 
The greatest care should therefore be taken, wherever castor 
poo')iac is made or stored, that no portion of it, or sweepings of the 
floors where it has been kept, should by any chance find their way 
into materials used as cattle food. It is also well to point out the 
risks that are run in the purchase of so-called “oil-cakes,” which are 
not made of pure linseed, but contain screenings of linseed, sweep- 
ings of floors, and other impurities, among which castor-oil seed may 
from time to time not improbably occur. 
J. W. Le.vther. 
CULTIVATED PLANTS OF THE FUTURE.' 
In' asking what are the possibilities that other plants than those we 
now employ may be utilised we enter upon a many-sided inquiry. 
Speculation is rife as to the coming man. May we not ask what 
plants the coming man will use 1 
There is an enormous disproportion between the total number 
of species of plants known to botanical science and the number of 
those which are employed by man. 
The species of flowering plants already described and named are 
about one hundred and seven thousand. Acquisitions from une.x- 
plored or imperfectly explored regions may increase the aggregate 
perhaps one tenth, so that we are within very safe limits in taking 
the number of existing species to be somewhat above one hundred 
and ten thousand. 
Now if we were to make a comprehensive list of all the flowering 
plants which are cultivated on what we may call a fairly large scale 
at the present day, placing therein all food and forage plants, all 
those which are grown for timber and cabinet woods, for fibres and 
cordage, for tanning materials, dyes, resins, rubber, gums, oils, 
perfumes, and medicines, we could bring together barely three 
hundred species. If we were to add to this short catalogue all the 
species, which, without cultivation, can be used by man, we should 
find it considerably lengthened. A great many products of the 
classes just I'ef erred to are derived in commerce from wild plants, but 
exactly how mucli their addition would extend the list, it is impossi- 
ble in the present state of knowledge to determine. Every enumer- 
ation of this character is likely to contain errors from two sources : 
first, it would be sui'e to contain some species which have outlived 
their real usefulness j and, secondly, owing to the chaotic condition 
of the literature of the subject, omissions would occur. 
1 Abstract of llic Presidential Address on “ Some of the Pos abilities of 
Economic Botany,” delivered before the American Association for the Advance- 
ment of Science, at Washington, 1891, by George Lincoln Goodale, 5I.D., LL.I>., 
Fisher Professor of Natural History. Harvard University, Cambridge, Mass., 
U.S.A. With additions by the Author. 
