Xxii INTRODUCTION. 
succeeding tables afford further information on the distribution of most of these orders. 
Those printed in italics are represented in Asia; some of them by solitary outliers; 
others, the Calycanthaceze for example, as fully as elsewhere, and these may yet be 
found in the mountains of Northern India. 
Not less remarkable is the small number of orders in the second table, especially 
in relation to the vegetation as a whole, of the two hemispheres*. With regard to 
the third, future explorations may probably reduce the total by about half a dozen 
orders, though not more. The fourth and fifth tables deal in different ways with 
orders included in the first; the fifth bringing also into great prominence the fact 
that there is exceedingly little ordinal peculiarity in the rest of the world, including 
the vast African region. The sixth table contains only one important natural order, 
namely the Dipterocarpee, which are known to extend to New Guinea, and some may 
possibly exist in tropical Australia. Altogether, twenty-six of the Indian orders are 
not found in Australia, and nineteen of them are not found in Mexico. 
Natural Orders not known to extend beyond America. 
Sarraceniacez. Batidez. 
Canellacez. Leitneriez. 
Vochysiacez. Lacistemacee. 
Cyrillaceze. Bromeliacez. 
Calyceracez. Mayacez. 
Lennoacee. Rapateacecze. 
Columelliacez. Cyclanthacez. 
The Galapagos islands are regarded as belonging to the American region. Besides 
the foregoing orders, which appear to be absolutely confined to America, there are the 
Humiriacez, which are American with one exception in W. Africa; the Turneraces 
are represented by a few species in the African region ; the monotypic genus Kissenia 
is the only member of the Loasacez found out of America; and, with the exception of 
the genus Rhipsalis, the Cactacee are wholly American. Hence it will be seen that 
between what is wanting and what is peculiar to America in natural orders, the balance 
is somewhat in favour of the latter. This completes the review of the leading features 
in the distribution of the natural orders. 
Something might be added here on the relative visible and spacious position occupied 
by the dominating orders in the different Floras; but as it is proposed dealing briefly 
with this part of the subject further on, some illustrations of generic and specific 
distribution are given first. 
GENERIC AND SPEcIFIC COMPOSITION OF THE FLORAS OF DIFFERENT AREAS. 
At page xix are given the relative numbers of orders, genera, and species in the Floras 
of India, Mexico, North America, and Australia ; and although no special significance 
* See vol. iv. pp. 202-207, 
