1 86 A NEW ZEALAND NATURALIST'S CALENDAR. 



it is unisexual, but I have always found it to be complete 

 in all its parts. It may be, however, that the organs are 

 not fully and equally developed in the different flowers. 

 Then there is no doubt also that the same species may be 

 hermaphrodite in one part of the country and in another 

 perhaps a warmer portion it becomes distinctly uni- 

 sexual. This is certainly the case in the white mapau 

 (Pittosporum eugenioidesj, which is always hermaphrodite 

 in and about Dunedin but is dioecious in most parts of the 

 North Island. 



As all forms of vegetable life tend to grow with increased 

 vigour as the weather gets warmer, it will be found that 

 now is the time to note and, if possible, combat those 

 parasitic fungi which so often attack cultivated plants. 

 For some years past a mildew has made its appearance on 

 the thorn hedges, and nearly always its attacks are notice- 

 able early in October. The chief objection to it is the 

 unsightly effect it has on the plants if it is strongly pro- 

 duced. It only shows itself on the young shoots, and when 

 these are pruned off they should always be burned. When 

 such parasites attack roses and fruit trees which being 

 semi-artificial productions are much more liable to suffer 

 from fungoid diseases than plants grown direct from seed 

 they seriously diminish the vitality of the plants and thus 

 impair the production of flowers and fruits. One of the 

 most effective modes of destroying or at least impairing 

 the vigour of these pests is to spray the plants with a weak 

 solution of calcium sulphide (made by boiling lime and 

 sulphur together in a kerosene tin and diluting the solution 

 with a considerable quantity of water). A very thin film 

 of calcium sulphide is thus left on the surface of the 

 leaves and this decomposes on exposure to the air and 

 leaves a skin of calcium carbonate and sulphur. It is 

 the latter substance which seems to be so obnoxious to the 

 fungi. 



In some gardens a curious fungus, a species of P^icc^nia, 

 attacks the leaves of anemones and prevents the plants 

 flowering. The leaves become thick and yellowish and are 

 covered, especially on the lower side, with dark spots. 



