202 SPENCER MOORE [SEPTEMBER 
not the genus have originated in Australia and passed thence via 
Eastern Asia, where it is represented by several species, into North 
America? Only on the hypothesis that a genus must have arisen in 
a larger area and that its presence in a smaller area must be due to 
migration, which is a mere begging of the question, can the possibility 
of a southern origin for Aster be denied. Mention may be made, too, 
of Bassia, in Mueller’s sense of the term, that is, as comprising Chenolea, 
Sclerolaena, Anisacantha, Threlkeldia, and part of Kochia as understood 
by Bentham. Of these Sclerolaena, Anisacantha, and Threlkeldia are 
endemic in Australia, and the two species of Kochia, referred to Bassia by 
Mueller, are also endemic there, Chenolea alone being extra-Australian 
with nearly one-third of its species restricted to the island-continent. 
Yet assia is held by Professor Tate to be a genus exotic to Australia ! 
So, too, Kochia proper has 19 Australian species, all endemic, leaving 
only 13 to be shared between South Europe, temperate Asia, North 
and South Africa, India, and North-West America; and when we 
remember that several peculiar genera allied to Kochia are exclusively 
Australian, is there anything extravagant in the opinion that proba- 
bilities point to this genus as having originated in Australia? And 
what shall we say of Atriplex, of which many species are Australian, 
and some of them extraordinarily abundant in individuals? The 
evidence for a southern origin of such genera as Ranwneulus and 
Clematis, Myosurus and Samolus is not so strong; but when we come 
to aquatics, such as Callitriche and Ceratophyilum and Potamogeton, all 
very extensively distributed, I do not see upon what grounds the 
possibility of a southern origin for some of them can be scouted, and it 
must not be forgotten that Wyriophyllum belongs to an order reaching 
its maximum of species in Australia. Then take the Grasses, an order 
very abundant in both hemispheres. Why may not such genera as 
Deyeuxia, Hierochloa, Stipa, and Eragrostis, to mention a few only, have 
originated in some southern land or lands, and migrated thence to their 
present homes in the north ? 
These are merely a few cases mentioned by way of example: by 
no means do they exhaust the list of genera for the southern origin of 
which there is at least some probability. But it may be objected that 
most of the genera cited above are not found in antarctic lands, and 
how, it will be asked, is their absence explained if they had a southern 
origin? I reply that, for all we know to the contrary, antarctic lands 
may, at some former time, have supported many supposed northern 
genera now not found there. This traverses Mr. Darwin’s opinion 
when he says:! “I am inclined to look in the southern as in the 
northern hemisphere to a former and warmer period, before the com- 
mencement of the last glacial period, when the antarctic lands, now 
covered with ice, supported a highly peculiar and isolated flora.” But 
with all deference to Mr. Darwin, why should the pre-glacial antarctic 
1 “Origin of Species,” 6th ed. p. 341. 
