yS Current Investigations in Economic Botany. 
—the cereals, farinaceous plants, legumes and fruits—and also 
several of the more important plants yielding fibres, dyes, and 
narcotics are plants of ancient cultivation. Amongst the plants of 
recent cultivation only, we find some pleasant fruits of minor 
dietetic value, some medicinal plants, but practically all the fodder 
and rubber-yielding plants, and others whose products have come 
into demand owing to changes in the conditions of life of the human 
races, and progress in the arts and sciences. 
As De Candolle well says, “ Men have not discovered and 
cultivated within the last two thousand years a single species which 
can rival maize, rice, the sweet potato, the potato, the bread fruit, 
the date, cereals, millets, sorghum, the banana, soy. These date 
from three, four, or five thousand years, perhaps even in some 
cases six thousand years. The species first cultivated during the 
Graeco-Roman civilization and later nearly all answer to these 
varied or more refined needs.We must come to the middle 
of the present [Nineteenth] Century to find new cultivations of any 
value from the utilitarian point of view, such as Eucalyptus globulus 
of Australia and the Cinchonas of South America.” Reviewing 
the subject in the Twentieth Century, we can add the rubber plants 
as noteworthy examples of new, cultivated plants. It would appear 
that at a very early stage in the history of agriculture in different 
parts of the world, the plants of the greatest value to man (for 
instance for food), were recognised and cultivated, and no plants of 
equal primary value having since been found, the early selected 
plants have been improved by cultivation and distributed from land 
to land to the exclusion of others. Within recent years a similar 
sequence of events has resulted in certain plants, for instance a few 
species of Cinchona and certain rubber-yielding plants being 
cultivated to the exclusion of others of less importance. Owing to 
reckless extermination by man one such plant, at any rate, 
DicJiopsis Gutta, has already passed practically into the group of 
economic plants only known in cultivation. 
The history of other economic plants may have been similar, 
and it is possible that plants now only known in cultivation were 
once wild species, and have been exterminated owing to various 
causes. On the other hand some, no doubt, have been so changed 
by selection through long ages that they have attained separate 
specific rank, and are not known out of cultivation, whilst their 
ancestral types may still survive and be regarded closely related 
wild species. 
(To be continued.) 
