154 LETTER XI. 



To this natural order belong the Breadfruit tree 

 (after which it is called the Breadfruit tribe), the 

 Mulberry, and many other exotic trees. For their 

 milkiness they are all most remarkable ; it is usually 

 of a somewhat acrid nature, as you may find in the 

 Fig itself ; sometimes is highly poisonous as in the 

 Upas tree of Java and some Indian species of Fig ; 

 or is ajiain Quite harmless and even nutritious in the 

 Cow tree of South America, to the trunks of which 

 the Indians repair in the morning with their jugs 

 and pails, just as the milkmaids of Europe to their 

 cow^s. It is, however, probable that in this instance 

 the milk is harmless only at a certain period of the 

 year, before the venomous principle is formed ; for a 

 AVest Indian plant called Brosimum, the young shoots 

 of which afford a wholesome food for cattle, is very 

 nearly the same as the Cow tree, and its old shoots 

 are poisonous. The Fig itself would not be fit to eat 

 if gathered green, because at that time the fruit 

 abounds in milk ; but when it is ripe all the milk has 

 dispersed, and then only it becomes the wholesome 

 fruit with which we are so well acquainted. 



Let this be a lesson to you never to judge hastily 

 of the affinities of plants, but to remember that it is 

 structure alone, and not vague external resemblances 

 or differences by which their relations are determined 

 botanically. 



The last of the tribes without corolla, which I shall 

 be able to lay before you, is one that is constructed 

 with still more simplicity than the last. They had 

 at least a calvx, but this has neither calvx nor corolla, 



