now amounts to 70,000 of which 15,000, are from n to 12 years 
old. 
After arriving upon the plantation and fitting up the labo- 
ratory required for the examination of the latex, and the testing of 
rubber on the spot, my first concern was to ascertain the exact 
species of the Castilloa on the plantation. This appeared to me 
all the more important, as there is one species of Castilloa known 
which yields plenty ot latex, but one containing no rubber and 
there appear to be several varieties yielding either a poor quality, 
or very little rubber. Of course, coming on the plantation in the 
rainy season, when the trees bear neither flowers nor seeds, was 
not exactly calculated to facilitate the botanical determination, and 
1 was therefore compelled to make a fairly close study of the 
morphological and physiological feature of the trees. On the other 
hand, it had to be borne in mind the fact that the whole of our 
present day information respecting the botanical characteristics of 
the various species of Castilloa, and the respective value of each of 
them for cultivation purposes, are in quite a hopeless state of con- 
fusion. 
According to the usual description, Castilloa elastica is a tree 
growing to a height of from 36 to 54 feet, the trunk at about 3 feet 
above ground attaining to a diameter of from 24 to 48 inches. 
The bark is smooth and yellow, the wood soft and perishable. The 
leaves are from 6 to 12 inches in length, of a clear and brilliant 
green, and their lower side is more or less covered with a growth 
of fine brown hairs. Very characteristic of Castilloa elastica is the 
phenomenon known as dimorphism of the branches and which con- 
sists in the branches which spring from the tree at an angle of 45 
degrees at a certain point rather abruptly taking up a horizontal 
position. I purposely omit entering here upon a discussion of the 
flowers and fruits of Castilloa elastica as a comparison of their 
characteristics with those produced by the trees at Las Cascadas, 
is at the present moment not possible. CROSS, the well known 
Kew botanist, describes these trees as growing to a height of from 
160 to 180 feet, with a diameter of 5 feet, but he gives no informa- 
tion respecting the age of these trees. In all probability these trees 
were an enormous age, to be reckoned by centuries rather than 
tens of years. J. H. Hart, Superintendent Royal Botanic Gardens, 
Trinidad, states that the oldest Castilloa tree there, is over 75 feet 
high and has a girth of 4 feet at three feet above ground. Some 
trees 15 years old are from 58 to 60 inches in girth. Against these 
two authorities we possess however the certain information that in 
Mexico, Honduras, Nicaragua and Ecuador, the height of Castilloa 
elastica varies between 40 and 60 feet. 
There are a number of other species or varieties of Castilloa, 
With regard to which a considerable amount of uncertainty exist. 
Indeed only one of these, C. tunu, Hemsley, is satisfactorily estab- 
lished as a distinct and different species, which, moreover, al- 
though containing a large quantity of latex, yields no India rubber 
at all. The C. markhamiana described by Collins as being found 
in the isthmus is considered by several very competent authorities 
