388 NOTES ON NATIVE FLORA OF NEW SOUTH WALES, IV., 



The distribution by wind is also most unlikely owing to the 

 distance, and also the fact that the air near the ocean is so 

 heavily charged with moisture that small objects are unlikely to 

 float very far. The only dry winds we have on the coast blow 

 out to sea. In the hot and dry interior the conditions are 

 different. 



The possibility of seeds being carried by birds requires more 

 serious consideration. It is well known that the seeds of this 

 particular She-oak are eaten by birds of the Black Cockatoo 

 family {Calyptorhynchus sp.), one known to many along the coast 

 as a so-called Macaw being especially fond of them. I have seen 

 this bird among these trees as far west as Nymagee, while on 

 eastern New South Wales they are usually to be found on the 

 Forest Oak (C. torulosa Ait). Clement Reid, F.R.S.,* gives an 

 instance of his finding, in an old chalk pit, the remains of a 

 pigeon which had met with an accident. Its crop was full of 

 broad-beans which were growing, though under ordinary circum- 

 stances they would have been digested and destroyed. But 

 although distribution occurs through the agency of birds, it 

 must be borne in mind that C. stricta is a dioecious species, and 

 ordinarily it would therefore be necessary for two trees to grow 

 fairly close together, one bearing male and the other female 

 flowers, before the propagation of the species could be accom- 

 plished. It would seem unreasonable, therefore, to look for any 

 accidental dispersal of seeds, forty miles apart, answering the 

 above conditions, and at the same time being placed respectively 

 on the northern and southern outcrops of the Narrabeen Shales. 



The cones of a Casuarina might certainly be carried b}' water, 

 though the seeds would probably be destroyed by a lengthy 

 immersion. The transporting agent in this case could only be 

 the ocean, but compliance with the conditions mentioned above 

 would probably be again necessary as regards the male and female 

 trees. As the home of C. stricta is in the southern part of Australia, 

 and it is not known to occur along the eastern coast of Northern 



* Origin of the British Flora, p. 30. 



