A CENSUS OP THE INDIAN POLYGONUMS. 
373 
expression as N. W. or Assam or ‘‘ Punjab”, or ‘‘ S. India 
which for the purpose of a precise survey are much too vague, or because 
they give only the name of the hamlet near which the specimen had 
been picked up. This latter practice of collectors is, in the eyes of the 
compiler of a paper like the present, just as reprehensible as the 
former, as it leads to much needless expenditure of time— to mention 
nothing else — in attempting to identify such insufficiently indicated 
localities by consulting a multitude of maps, gazetteers, books of 
travel, etc., each of which probably has its own particular system of 
mis-spelling Indian place-names. Sheets bearing such expressions 
as N. W. Himalaya”, Assam ”, are quoted only where they are the 
sole representatives of the species in the Calcutta Herbarium, or 
where properly localised specimens are very few. 
The artificial key does not pretend to the unerring accuracy of an 
automatic machine, neatly naming and ejecting every Polygonum 
in whatever condition thrown into it, but it is hoped that it may aid the 
botanist unfamiliar with the Indian species to approximately place his 
specimens, so that he can compare them with the descriptions in the 
Flora of British India, with as little waste of time as possible. The 
tables of distribution explain themselves, and any additional notes 
merely have the merit, if it be such, of saving the reader a little 
mental and visual exercise. 
The botanical area considered is practically the same as that dealt 
with in the Flora of British India. Ceylon, however, is here omitted, 
partly because that island has now a Flora ” of its own, partly 
because the Calcutta Herbarium has little beyond Thwaites’ distribution 
numbers. The British Indian Empire, with Nepal, Sikkim, a small 
part of Tibet, Bhutan, the hills just to the east of Bhutan, and the 
Malay Peninsula, is taken as the unit. This being itself botanically a 
sub-area, is divided into sub-sub-areas, and these again into districts, 
as detailed below. 
The sub-sub-areas are, in the main, similar tp those adopted by 
Mr. C. B, Clarke in his paper on the sub-sub-areas of British India 
\vi\hQ Journal of the Linnean Society ^ vol, xxxiv, but the writer’s 
sub-sub-araes agree more with the political boundaries, which are 
more convenient for practical purposes, and probably will not be found 
to stand much in the way of drawing any phytogeographical infer- 
ences from the facts set forth. In the list of species, the distribution 
of each one is given in the order of the sub-sub-areas detailed below 
and within each sub-sub-area, where such sub-sub-areas are further 
sub-divided into districts, in the order of the districts. Each sub-sub- 
area, and wdthin it each district, has its own number ; but in every case 
the name as well as the number of the sub-sub-area or district is 
