It must also not be forgotten, that notwithstanding the general tendency to a tropical flora, the natural result of the low elevation and great aridity of these hills, a portion of the vegetation even at the lowest levels consists of plants of European forms, such as characterize the temperate vegetation of the Himalaya. I do not here refer to what may be called the cold-weather vegetation of the plains of north-western India, at which season, the temperature of the air approaching to that of the summer of the temperate zone, a considerable number of European plants make their appearance in corn-fields and along the banks of water-courses; as, for example, _Veronica Anagallis_ and _agrestis_, _Anagallis_, _Medicago_, _Melilotus_, _Potentilla supina_, _Juncus bufonius_, _Arenaria serpyllifolia_, _Heliotropium Europæum_, and many others. These naturally occur at the same season, in the low valleys among the hills, in similar situations. The circumstance to which I desire to advert, is the occurrence at very low levels among the mountains, during the hot and rainy seasons, of species belonging to genera characteristic of temperate climates, and which therefore are the prevailing forms at considerable elevations on the Himalaya. As instances, I may adduce the occurrence in the valley of the Gambar, at elevations not exceeding 3000 feet, of species of _Thalictrum_, _Fragaria_, _Rosa_, _Rubus_, _Berberis_, &c., &c. This remarkable fact has been ascribed by Jacquemont[1] to the obscure influence of the mountains; and as the genera just enumerated never occur in the plains of Upper India, it appears evident that the mountainous nature of the country must be viewed as an essential element in the reasons for their descent. These, with some others which also occur at low levels in the Himalaya, appear to be in all parts of the continent of India those genera of temperate climates, which descend to the lowest altitudes. Some of them were found by Dr. Hooker on Parasnâth, a hill in upper Behar, the elevation of which does not exceed 4000 feet; and they are all natives of moderate elevations on the Nilgherries and in Ceylon, as well as on the Khasya mountains in eastern Bengal.