Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/85

Rh influence on the distribution of its plants, we will content ourselves with quoting here the figures for the various stations as they stand in the last Club report. The stations for which no altitude is given are very little above sea level.

This is just as might be expected, the minimum along the coast, and the quantity growing gradually greater inland to the maximum in the vicinity of the western ridges.

Wind.—We ought not to pass entirely unnoticed the influence which the force of the wind has upon vegetation. Take a maritime station, like Shields, for instance, and compare it with a sheltered inland locality like Bywell, and it is probable that the force of the wind, as measured by an anemometer, is twice as great on the average of the whole year at the former place as at the latter. The consequence is, that along the whole coast, exposed as it is to the full force of the cold breezes of the east, trees of any kind can attain to a moderate height and luxuriance only in sheltered situations; and no doubt, the same reason causes our springs to be later, and our climate to be more unfavourable for herbaceous plants that love warmth and shelter, in comparison with Yorkshire and the Midland Counties, than the mere figures of temperature indicate. We shall have occasion, in another part of the work, to point out how rapidly, in Northumberland and Durham, the characteristically southern plants thin out.