REGIONS AND AREAS OF DISTRIBUTION. 553 
which has 28 Australian and 190 South-African species, yet those 
seven form a very prominent feature in the Composite flora of 
both, constituting above a third of the total number of species in 
Australia and above a fourth in South Africa. There are no spe- 
cies (except such weeds as Cotula coronopifolia) identical in the 
two regions; but one in each of them of Athrixia and two or 
three of Helipterum and Helichrysum are very closely representa- 
tive. Of Cassinia, the South-African species (Rhynea) belongs to 
a section not met with in Australia, but represented by four spe- 
cies in New Zealand. To these representative plants must be 
added Cymbonotus, an endemic Australian monotype of the very 
distinct tribe (scarcely more than a Linnean genus) Arctotidex, 
which, besides this one species and a very few stragglers into 
tropical Africa, is exclusively South-African. This approximation 
of the Composite of Australia and South Africa may possibly date 
from times less ancient than those in which they established a 
communication between the New and the Old World; and it may 
even have been less remote than the period in which flourished the 
common parents of Australian and South-African Proteacee and 
Restiacez, or of Australian Epacrides and South-African Ericeæ ; 
for it is exemplified not in tribes only, but also in identical genera 
and sections. On the other hand, the separation may be supposed 
to be either more distant in point of time or more complete phy- 
siologically than in the case of Pelargonium, Nicotiana, and others, 
where the specific divergence of Australian from South-African 
or South-American races may be said to have only commenced. 
The connexion between Australia and tropical Africa exempli- 
fied in a few arborescent or large shrubby Cesalpinee, Mimosese, 
Malvacex, &c. (Cassia, Erythrophleum, Adansonia, Sic.) has no 
instance, as far as I am aware, in Composite, perhaps owing to 
the absence of arborescent forms. With tropical Asia the northern 
and north-eastern coasts of Australia are more nearly connected ; 
and iu many orders tropical Australia possesses common or endemic 
genera and species forming part of the general tropical Indo-Aus- 
tralian flora. In Composite these Australian representatives of 
the flora are few, owing to the general poverty of the order in that 
region. There is in tropical Australia only one endemic genus 
CPleurocarpea), which may be said to be the Australian represen- 
tative of the peninsular Indian Adenoon. The two tropical Old- 
World genera Epaltes and Ohrysogonum (Moonia) have, the former 
two, the latter three, Australian endemic species, without any 
