242 NOTICES OF BOOKS. 



investigations are to be continued.— H. W., in ** Silliman's Journal,'* 



July, 1875. 



The Kesting-spoees of Peronospora infestans (the Potato 

 PuNGUs). — Mr. AV. G. Smith has added to the already high apprecia- 

 tion in which he is held as a microscopist by his very important dis- 

 covery of the true sexual reproduction and of the resting-spores of this 

 Peronosjjora ; and has thus supplied the missing link in our knowledge 

 of the fungus, which is of the highest practical importance in 

 relation to the disease. The history of the discovery has been fully 

 given in the '* Gardener's Chronicle " for July 10th, 17th, and 24th, the 

 "Journal of Horticulture " for July 22nd, and " Xature " of the same 

 date, where will be found illustrations of the antheridia and oogonia, 

 and of the resting-spores resulting from their union. By Mr. 

 Smith's kindness we have had the opportunity of examining 

 his original drawings, which exhibit most clearly and completely 

 the whole life histoiy of the parasite. The sexual organs and 

 resting-spores were formed in the tissues of the leaf and stem as a 

 result of maceration in water, and it may be that excessive moisture 

 is necessary for their production. As the hard, black, worted resting- 

 spores are clearly visible when a strong light is thrown through the 

 leaf, it is somewhat remarkable that they have not been previously 

 detected ; perhaps the rather prevalent notion lately that they were 

 likely to be found in some other plant than the potato may have had 

 some share in this. The whole of the structures are closely similar to 

 those of other species of Peronospora in which the sexual organs and 

 dormant spores have been well known for some years. The practical 

 bearings of Mr. Smith's discovery are evident enough to be appreciated 

 by all, and likely to overshadow its scientific importance. 



IIJotic0;ef of 25ooftiSf» 



Botanischer Jahreslericht : Systematisch geordnetes Repertorium der 

 botanischen Literatur aller Lander. Herausgegeben von Dr. 

 Leopold Just. Erster Jahrgang, 1873. Zweiter Halbband. 

 Berlin, 1874. 



We have already (Journal of Botany for March, p. 93) noticed the 

 publication of the first part of this laborious resume of the botanical 

 literature of 1873. The second part is considerably larger in bulk 

 than the first, the two together making a volume of over 700 pages 

 The labour of such a compilation must have been immense ; and we 

 are too well acquainted with the liability of even the most careful 

 editor to overlook some papers of importance to be severe on any errors 

 of omission which may occur in a volume of this description. StilJ, 

 when we find in it no reference to papers published during the year 

 1873 of so much importance as Dr. M'Nab's researches on the de- 

 velopment of the flowers of Welwitschia, Prof. Oliver's account of the 

 Botany of theSpeke and Grant Expedition, and Mr. Bentham's admir- 

 able review of the classification a^d distribution [of Composites, we 

 cannot but entertain some doubt as to the completeness of the collec- 



