What I have said of Epilobium above, is true of Typha and Arundo, both now passed flowering, and both found in India, to a considerable extent.

Royle’s idea of the comparatively greater extent of distribution of water plants is not I think correct, in the sense he seems to entertain it; to be so, the species should be the same, which they are certainly not.  It is only with pre-eminently aquatic forms that the annual temperature can be more equalised than obtains with strictly terrestrial plants.  The humidity which may appear connected with the rapid evaporation in these countries, and which obtains? in the vicinity of all bodies of water, may account for the appearance here of Arundo, etc.  All genuine aquatic types have leaves involute in vernation?

The least valuable of all northern forms, are those associated with cultivation, especially if they be annuals, because in the first place they may be acclimated species, a circumstance of great importance; and in the second, because if annual, they are confined to the cold season.  All such forms have probably migrated into these countries, they have come from the westward:  this shows us why at almost equal elevations they are most common, the nearer we approach to the elevated regions towards the west, because it is self-evident that the nearer we approach the regions whence they have migrated, the more abundant and diversified will the migrating plants be, only particular species having the power of extending the range of migration.

When all the Indian plants hitherto met with, have been tabulated; when all their respective heights at which they have been found have been determined; when their more strictly geographical sites have been fixed; when we have some data as to the quantity of humidity pervading their localities; then, and not till then, shall we be able to legislate for the geography of Indian botany.

The Botanist who travels without the means of determining these points, destroys half the value of his collections.

December 16th.—­Yesterday was very raw and cloudy, to-day clear as usual, towards 1 P.M. a strong north-east wind occurred for a short time as usual, because once or twice before, it occurred after threatening weather.

Rationale.—­It blows from the nearest snow to supply the rarefied air in the valley heated by the sun, even now tolerably powerful; it blows for some days so long as a vacuum is formed, and discontinues when clouds again appear; hardly so, as it before only blew for three or four days, although several more elapsed before clouds re-appeared:  it may however be dependent on each fresh fall of snow in the hills.

26th.—­Cloudy morning, forenoon fine, clear and calm.

Mosses are the analogues of Zoophytes; these analogies are to be looked for in the most striking and most constant parts of the organization of the divisions of nature.