INTRODUCTORY ESSAY. 
15. Verbenaceso has most species 
in the Tropics; nex 
/, South-west ; fewest in t 
he South-cast. 
16. Loganiaeea> „ 
Tropics , 
South-west 
South-oast. 
17. Cruciferee „ 
South-east , 
South-west „ 
Tropica. 
18. Loranthacea> „ 
Tropics 
South-cast „ 
South-west. 
19. Lobeliacea) „ 
South-west , 
South-east „ 
Tropin. 
20. Urticea* 
Tropics 
South-east „ 
South-west. 
21. Ranunculaceffl „ 
South-east 
South-west 
Tropics. 
22. Polygaleae „ 
South-west 
, South-east „ 
Tropics. 
23. Solaneae 
Tropics 
, South-east „ 
South-west. 
2-4. Lentibularineae „ 
South-east 
, South-west 
Tropics. 
25. BoragineaD . „ 
Tropics 
, South-west „ 
South-east. 
The sequence in this case is wholly inverted from what obtained in A and B, and we have— 
Fourteen twenty-fifths attaining their maximum in the Tropics. 
Six twenty-fifthB „ „ South-east, 
Five twenty-fifths „ „ South-west. 
This accumulation of ordinal and generic peculiarity of Australian vegetation in the south-west 
quarter of the continent, as compared with the south-east especially, is a very remarkable feature; 
it would still have been very striking had there been any contrasting peculiarity of climate «>r lurfaoe 
between these districts, which is not the case. 
An examination of the proportions which the largest Natural Orders bear to the whole Flora 
affords very important data for determining the relations of a Flora. 1 find that half the Australian 
species arc" included under the following Orders, which I have here arranged nearly in the order 
of their numerical extent, and contrasted them with those of some other countries. 
Hence it appears, that of the nine Natural Orders which together include upwards of half the 
known Australian Flowering Plants, three Orders are similarly characteristic of all the other areas 
compared, two of three areas, and two of two areas. In other words,— 
Composite, Leguminosa?, and Gramineae, are found in all five areas. 
Cyperacea? and Orchidea?, in three. 
Epacrideae (Ericea?) and Myrtaceae, in two. 
Q-oodeniaceae and Proteacea?, in Australia alone. 
Itude as the above data and methods of comparison are, they appear clearly to corroborate the 
