Dispersal of Herbaceous A ngiosperms. 591 
with plants, and either connecting Australia, New Zealand, and South 
America directly or providing a much readier means of transit than those 
available at present, has been appealed to by almost every one who has 
studied the distribution of the Antarctic flora. It seems more likely, from 
the absence of any considerable Patagonian element in the Australasian 
fauna that the Antarctic connexion was rather in the nature of a large 
archipelago, as Hutton (11) and Macloskie (13) have suggested, than of 
a continuous bridge. ‘ Such conditions seem to speak to us ’, says Macloskie 
(13, p. 959 ), ‘of a broken chain rather than a continuum of land; of an 
archipelago on a grand scale, some of its components of the continental 
kind as to dimensions ; and with interruptions which secured animal and 
vegetable isolation ; yet sufficient to permit occasional passage of seeds and 
of birds, and an occasional transit of a quadruped, a sort of quasi-Fuegian 
archipelago on a larger scale.’ 
Recent geological evidence lends strong support to the hypothesis of 
a temperate Antarctic continent, for remains of Ferns, Conifers, and Angio- 
sperms have been obtained in considerable abundance from the Tertiary 
deposits of Seymour Island, near Graham Land. 
The array of northern herbs in temperate South America, New Zealand, 
and Tasmania and a part of those in Australia have therefore in all 
probability reached the Antipodes from the north along the Andes and 
across Antarctica. The absence of many of these plants from the northern 
Andes to-day is probably due, as Wallace suggests, to the interruption of 
such favourable conditions as a lowered snow-line, which very likely assisted 
the migration of temperate forms in the past. It seems very probable that 
past glacial periods, even perhaps the last Ice Age in the northern hemisphere, 
may have aided the invasion of the northern flora by increasing the area of 
temperate regions in the tropics. 
That there has also been immigration along the mountains of south- 
eastern Asia and the East Indies into the southern hemisphere is indicated 
by the presence in Australia of many northern genera which could have 
entered by no other route. Wallace has' remarked on the fact that the 
‘ northern ’ flora of Australia consists of two distinct elements, one which 
closely resembles that of New Zealand and South America, and which is 
mainly confined to the south-eastern part of the continent, and includes all 
the species which are identical with European ones ; and another of 
European genera, * usually of a somewhat more southern character ’, which 
do not occur in New Zealand or South America, and which are represented 
by very distinct species. The latter portion of the flora presumably reached 
Australia through southern Asia at a time when immigration from the north 
was easier than at present, and the presence of many palaearctic forms in 
the mountains of the East Indies points out the highway which was 
traversed. That the invasion over this route was interrupted considerably 
