32 
JOUENAL OF THE ROYAL HORTICULTURAL SOCIETY. 
we require more evidence, because the differences between the two genera- 
(according to description) are such that no human interest is likely tO' 
have evolved directly or indirectly. It has been sought, I believe, to 
establish a new genus upon some strain of tuberous Begonias, but I 
question whether the difference relied upon is any greater than differences; 
already existing in the genus Begonia. The difference between species 
and genus is only one of degree, and of species there is quite a sufficient 
number for the illustration of evolution. 
Wheat, Barley, Eye, and Oats are all the result of domestic evolution,, 
and I need hardly say that evolution is proceeding to-day as fast as 
selectors and breeders can push it forward. An interesting case we have 
in the Opium Poppy (Papaver so^nniferuvi), an evolute from Papaver 
setigerum. The Olive, Bice, Potato, and Grape Vine are all forms of 
cultivation. 
Mons. Alphonse de Candolle has written a very interesting book upon 
the origin of cultivated plants, limited, however, to what we call economic 
plants. I have said that the process of evolution has been pushed so 
far that we cannot now recognise the originals. I do not say that this 
process accounts for all our ignorance of the origin of long cultivated 
plants ; but it does, I believe, account for much of our ignorance. It 
does not account for such cases as Arachis hypogcea, ArracacJm escu- 
lenta, Sacchanim officinarum, and Sechium edule. The following list 
(not intended to be complete) I extract from De Candolle 's book, and 
from the sectional headings opinion may be formed with regard to the 
plants beneath. In some cases the originals have become extinct, or may- 
yet be found. 
Seen and gathered in the same condition, but by a single botanist in a 
single locaHty : — 
CucurUta maxima (Melon Pumpkin). 
Vicia Faha (Broad Bean). It has been suggested that this is a 
derivative from 7. narhonensis. I think it unlikely. 
Nicotiana Tahacum (Tobacco). 
Seen and mentioned, but not collected, in the same condition by one 
or two more or less old non-botanical authors, who may have been mis- 
taken : — 
Triticum vulgare (Wheat). 
Gathered wild by botanists in several locaHties under forms shghtly 
differing from the cultivated plants, but which most authors do not hesi- 
tate to class with the same species : — 
Olea europcsa (Olive). 
Oryza sativa (Rice). 
Solanum tuberosum (Potato). 
Vitis vinifera (Grape). 
Gathered wild by botanists in several locaUties under forms considered 
by some authors as distinct species, and by others as varieties : — 
Allium Porrum (Leek). 
Cichorium Endivia (Endive). 
Crocus sativus (Saffron Crocus). 
Cucumis Melo (Melon). 
Ciicurhita Pepo (Pumpkin Gourd), 
