on or near the summit:— Two species of Violet, three of Ranunculus, three of
Impatiens, eight or ten of Rubus, and species of Primula, Hypericum, Swertia,
Convallaria (Lily of the Valley), Vaccinium (Cranberry), Rhododendron,
Gnaphalium, Polygonum, Digitalis (Foxglove), Lonicera (Honeysuckle),
Plantago (Rib-grass), Artemisia (Wormwood), Lobelia, Oxalis (Wood-sorrel),
Quercus (Oak), and Taxus (Yew). A few of the smaller plants (Plantago major
and lanceolata, Sonchus oleraceus, and Artemisia vulgaris) are identical with
European species.
The fact of a vegetation so closely allied to that of Europe occurring on
isolated mountain peaks, in an island south of the Equator, while all the lowlands
for thousands of miles around are occupied by a flora of a totally different
character, is very extraordinary; and has only recently received an intelligible
explanation. The Peak of Teneriffe, which rises to a greater height and is much
nearer to Europe, contains no such Alpine flora; neither do the mountains of
Bourbon and Mauritius. The case of the volcanic peaks of Java is therefore
somewhat exceptional, but there are several analogous, if not exactly parallel
cases, that will enable us better to understand in what way the phenomena may
possibly have been brought about.
The higher peaks of the Alps, and even of the Pyrenees, contain a number of
plants absolutely identical with those of Lapland, but nowhere found in the
intervening plains. On the summit of the White Mountains, in the United States,
every plant is identical with species growing in Labrador. In these cases all
ordinary means of transport fail. Most of the plants have heavy seeds, which
could not possibly be carried such immense distances by the wind; and the
agency of birds in so effectually stocking these Alpine heights is equally out of
the question. The difficulty was so great, that some naturalists were driven to
believe that these species were all separately created twice over on these distant
peaks. The determination of a recent glacial epoch, however, soon offered a
much more satisfactory solution, and one that is now universally accepted by
men of science. At this period, when the mountains of Wales were full of
glaciers, and the mountainous parts of Central Europe, and much of America
north of the great lakes, were covered with snow and ice, and had a climate
resembling that of Labrador and Greenland at the present day, an Arctic flora
covered all these regions. As this epoch of cold passed away, and the snowy
mantle of the country, with the glaciers that descended from every mountain
summit, receded up their slopes and towards the north pole, the plants receded
also, always clinging as now to the margins of the perpetual snow line. Thus it is
that the same species are now found on the summits of the mountains of