OF THE INTERIOR OF WESTERN AUSTRALIA. 253 
GENERAL CONCLUSIONS RESPECTING THE DESERT FLORA. 
From the table on p. 240 we learn that of the 849 phanero- 
gamous species—exclusive of introduetions—composing the flora 
of the West Australian desert, 537, or 63:2 per cent., occur in 
the South-west corner, while 371, or 43:7 per cent., are met with 
in the Eastern Colouies. Moreover, while of the 537 South- 
western species, 276 are not known from the Eastern Colonies, 
except that 43 of them extend into South Australia, of the 371 
Eastern species only 100 are not found in the South-west. 
Viewing the flora as a whole, then, it would seem to consist of 
two elements—a main one, derived from the South-west, and a 
subsidiary one, passing in from the East. To this must be added 
an endemie element, amounting as we have seen to 146 species, 
or 17 per cent. Doubtless this is only a rough method of stating 
the case, for it may well be that some of the species restricted to 
the desert and the South-west may have originated in the desert 
and migrated thence ; and the remark applies with equal force to 
some of the Eastern species which do not penetrate beyond the 
desert into the South-west corner. It is, however, difficult to 
understand why a species should have migrated from the desert 
in one direction rather than in the other; and inasmuch as the 
chances of extension in either direction would be approximately 
equal, the statement given above probably represents the real 
facts. 
The orders best represented in the desert are, Composite: with 
97 species (11 per cent.); Zeguminose, with one less ; and Myr- 
tace@, with 89 species (rather more than 10 per cent.); and 
between them these monopolize the flora to the extent of nearly 
3. In the second flight, with 35 species and over, are five orders : 
Amaranthacee and Proteacee, each with 47 species (rather more 
than 5 per cent.) ; Goodeniacee, with 42 species (5 per cent.) ; 
Graminee, with 41 species, and Myoporinee with 35 species (4 per 
cent.). These 8 orders have 491 desert representatives, or nearly 
58 per cent. of the whole flora. The remaining 42 per cent. is 
thus shared between no less than 65 orders. 
The prevalence of Composite, and the relatively large number 
ofits desert species with a wide range of distribution through the 
island-continent—these faets are doubtless due to the pappus with 
Which the achenes of these plants are provided. The statement 
T2 
