46 THE VICTORIAN NATURALIST. 



are generally adapted for the different seasons of the year, and we 

 have spring, summer, and winter spores, each with their own 

 special characteristics, but this division must not be interpreted 

 too strictly in a climate such as ours. In the early spring the 

 aecidia or cluster-cups are produced, with their numerous spores 

 arranged in rows, and it is a special feature of these spores that 

 they are the result of the fusion of sexual cells. Then the 

 summer or red-rust spores or uredospores succeed, to be followed 

 by the winter or resting spore, the so-called teleuto or finishing 

 spore. This gives rise on germination to a special spore, which 

 forms the starting point of this strange, eventful history. So we 

 have a continuous succession of spore-forms, starting with the 

 product of the teleutospore, which gives rise to the aecidiospore, 

 when the first rush of growth commences in the spring, then the 

 uredospores, chiefly during summer, when steady growth is main- 

 tained, and finishing up in the autumn with the teleutospore, 

 capable of remaining dormant during the winter and starting into 

 fresh life in the spring. 



This is the complete series, and while the teleutospore is 

 believed to be a constant factor in the cycle, either the aecidio- 

 spore, uredospore, or both may be omitted or suppressed, as in 

 the common Mallow Rust, which produces only winter spores, and 

 can forego a resting period. 



Number of Australian Rusts. — In attempting to give you the 

 number of Australian rusts known at the present time, I do not 

 for a moment wish you to understand that it is complete and 

 final. Where would the charm be in going into the bush to hunt 

 for rusts if you had the slightest suspicion that the numbers were 

 up, and that no fresh discovery could possibly reward your zeal ? 

 On the contrary, it is one of the delights of the naturalist here, 

 the pleasures of anticipation ; and, speaking for the fungi generally, 

 and particularly of the micro-fungi, I may say that there are still 

 entire districts unexplored which would probably yield a rich 

 harvest. In Dr. Cooke's " Handbook of Australian Fungi," 

 published in 1892, there are 72 species recorded, and now there 

 are 162, or exactly 2^ times that number, known. Even since 

 the numbers were given in ray latest work an important addition 

 has to be made, for m the examination of the very extensive 

 collection of acacias in the National Herbarium an Aecidium was 

 found on Acacia farnesiana Willd., and this is the first time such 

 a form has been found on acacias in Australia. That just shows 

 how likely it is that fresh forms will be discovered whenever 

 they are specially looked for, and there is a promising field in the 

 numerous (over 300) acacias occurring in Australia. It has also 

 to be remembered that the aecidial or uredo stage is not the final 

 stage of a rust, but that teleutospores probably exist, so when an 

 Aecidium is found it suggests one other stage at least of the same 



