THE VICTORIAN NATURALIST. Ill 



family is defined and limited to six genera — viz., Podosphcera, 

 SphcerotJieca, Uncinula, Microsphcera, Erysiphe, and Phyllactinia. 

 Then the morphology and life-history of the group are given. 

 The superficial mycelium is attached to the host-plant by means 

 of haustoria in the epidermal cells. The reproductive phase is 

 characterized by the production of an oidium or conidial stage, 

 adapted for rapid reproduction during summer and early autumn, 

 followed by the perithecial stage, in which the asci containing 

 spores are formed, and these resting-spores carry the plant over 

 the winter. A rapid historical survey is made from the first 

 mention of this group of plants by Linnaeus in 1753, through the 

 classic researches of Leveille, Tulasne, and De Bary down to the 

 present time. The connection between host and parasite is next 

 referred to, and the practice is condemned of making the 

 connection of a parasitic fungus with a certain host-plant of 

 specific importance. The number of previous species is con- 

 siderably reduced from the fact that a wide view is necessarily 

 taken of species, since a large mass of material from all parts of 

 the world was available, and the principle is laid down that 

 classification rests primarily on morphological characters. In 

 the distribution of species of this family it is pointed out 

 that while they have practically a world-wide distribution, their 

 headquarters are in the North Temperate Zone. Only 5 of the 

 49 species are recorded for Australia, and it is interesting to note 

 that a new species from New South Wales in 1899 {Uncinula 

 australiana, M'Alp.) has also been found in Japan. The 

 economic aspect of these parasitic fungi is not neglected, for, in 

 addition to their life-histories as far as known, instructions are 

 given as to the best methods of treating the various diseases 

 caused by them. A detailed classification and description of the 

 various species are given, with keys to the genera and species, so 

 as to render recognition easy. The value of the work is con- 

 siderably enhanced by the copious bibliography, together with a 

 valuable host-index, and the nine plates containing 175 figures 

 are models of clearness. In this volume all the principal facts 

 connected with this interesting group of fungi are given, and no 

 one who studies modern mycology, or is scientifically interested 

 in the " Mildews," which so seriously affect the vine and the 

 strawberry, the apple and the pear, the hop and the rose, can 

 afford to dispense with it. — D. M'Alpine. 



The Baron von Mueller Grave Memorial — His Ex- 

 cellency the Governor-General, Lord Hopetoun, has consented to 

 unveil the memorial over the grave of the late Baron Sir F. von 

 Mueller, K.C.M.G., in the St. Kilda Cemetery on Tuesday after- 

 noon, 26th November, when a number of prominent citizens have 

 signified their intention of taking part in the ceremony. 



