Page:The Botany of the Antarctic Voyage.djvu/384

348 of mountain plants, having the upper limit in elevation which they attain sharply defined, throughout several degrees of latitude, but which descend and assume other aspects in a warmer climate. This, also, I have attempted to express on paper by dotted lines drawn down to the sea-level, from the Chilian positions of F. betuloides and F. obliqua. The abrupt termination of all the Beeches at about lat. 35&deg;, occurs where the equally sudden change in the climate of northern and southern Chili takes place. These trees, like all extra-tropical plants, require a certain degree of cold, and in pursuing their range towards the warmer parallels, they ascend the mountains. They are, however, even more dependent upon humidity and an equable climate than on temperature; and being further impatient of vicissitudes and dryness, they will not pass beyond the influence of those S. W. winds which drench all parts of western South America, alpine and lowland, south of the parallel of 37&deg;.



One of the few attractions of spring in Antarctic America, is the bursting of the leaf and flower buds of the deciduous-leaved Beech from their resinous gummy scales; when a delightfully fragrant odour pervades the woods. The unfolding of the plaited foliage was watched with great interest, for we had not witnessed for years any process so closely resembling that of an English spring. It recalled Linn&aelig;us' enthusiastic description of the first burst of the birch leaf in Lapland.