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SP Pee 
PO ee et eo 
TRANSACTIONS OF THE SECTIONS. 75 
Several, indeed, of the species are identical with those found in these distant coun- 
tries, separated on one hand by the cold and arid deserts of Tartary, and on the other 
by the hot and equally arid plains of India and of Africa, as well as the sea. Some 
of the peaks however, having the characteristics of polar climates, have also that of 
the vegetation ; and it is curious to see all the families and many of the same genera 
on these isolated peaks and the remote Melville Island, The northern face of the 
Himalayas, or the Tibetan region, has, the closest resemblance in its genera, and even 
many of its species, to that of the Atlas mountains and of Siberia, with a sprinkling 
of the Mediterranean flora, The author, having taken this general view, remarked 
on the correspondence between the vegetation of even distant countries wherever 
there was a correspondence in climate, and called attention to the curious resem- 
blance in the belts of vegetation at different elevations on the Himalayas with that 
of different latitudes, as detailed in the author’s ‘ Illustrations of Himalayan Botany,’ 
Dr. Royle inquired with reference to some of the geological explanations of successive 
elevations of mountain ranges—at what period the vegetation of the peaks, for in- 
stance, came to resemble that of polar regions ? 
Among the various subjects, Dr. Royle stated, to which he might draw the notice of 
the Section, there was one, he thought, particularly worthy of the attention of those 
favourably situated for making observations; and that was the thick vegetation which 
clothes the surface of many of the lakes of India. Dr, Royle stated that he himself 
having been chiefly in the north of India, had not seen this vegetation to the extent 
in which it existed in the more southern parts of India; but even there it was suffi- 
ciently substantial to support numbers of the smaller Gralla, and among them the 
Chinese Jacana. But having on one occasion been detained on the banks of some 
of these lakes on the north-west of Bengal, he had been much struck with the thick 
and varied vegetation of the floating masses with which their surfaces were covered. 
These consist of numerous stems, leaf and flower-stalks of a variety of plants closely 
interlaced and matted together, the younger parts requiring both light and air for 
the performance of their functions, finding their way to the surface; while the older 
are pushed downwards, when the more herbaceous parts rot and decay. Among 
these plants are most of the genera and some of the species even, which are found 
in similar situations in Europe; but with them such plants as Avschynomene aspera 
with its thick cellular stem, Convoluulus edulis, Herpestes Monniera, and Utricularia 
stellaris, Marsilea quadrifolia, Trapa bispinosa and bicornis, with species of Polygonum 
and Dysophylia verticillata, The last is particularly interesting from its long jointed 
and striated stem with its whorls of leaves. Of most of them it may be observed that 
they have little or no rvot ; the floating stems are long and slender, very cellular, with 
the vascular bundles arranged round the circumference, with little or rather with no- 
thing like bark. By Dr, Buchanan Hamilton these lakes have been seen of much greater 
extent, and covered with a much more dense vegetation, so much so, indeed, that he 
describes the floating masses to be sufficiently substantial for cattle to graze upon the 
grasses with which they became covered, but that occasionally some fall through and 
are lost. He describes, moreover, some bushes and trees as growing in the midst of 
the water, and among them a Rose, a Barringtonia, and a Cephalanthus, 
It is hardly possible to witness such vegetation, without calling to mind some of 
the explanations given of the formation of coal in the ancient periods of the world, 
and of the indications often presented to us in coal fields of a tropical vegetation, in 
situations where no tropical plants could now grow. But without proceeding fur- 
ther, it is interesting to compare the vegetation of these lakes with that of the Indian 
coal-fields of Burdwan, which are in their immediate vicinity. The first thing that 
will strike an observer is, that there is no remarkable difference between what was 
the former flora of these localities, and what might take place at the present day. 
One great difference is certainly observable in the Indian coal-fields, and that is the 
immense mass of ferns of which they seem to be composed, while no ferns are at 
present found in their neighbourhood. This however is owing to the country and 
the plains of India generally being open, and therefore extremely hot and dry for 
some months in the year. One fern, Asplenium radiatum, is found near Delhi, in the 
_ sides of wells, in the peninsula of India, and also in Arabia. Cheilanthes dealbata and 
Lygodium microphyllum occur in the neighbouring Rajmuhl hills. But in the same 
latitude, and not very distant, where the country is covered with forests, producing 
