172 Reviews

genes in host and parasite. The main chapters concen-trate on cytological changes during infection, inducedresistance, phytoalexins, and the mediation of specifi-city. An attempt is made throughout to find someunifying principles that are consistent with the verydiverse results obtained in research in these variousareas. In general, Professor Deverall argues from thebasis that the' low infection type' reaction is uniquelyspecified in gene-for-gene systems in developinghypotheses on the expression of specific resistance.The hypersensitive reaction, the production of phyto-alexins, and their probable association are criticallyreviewed, with the conclusion in general that thesephenomena are closely involved in specific resistance.

The monograph is quite short and does not attemptto review the whole field exhaustively. Instead, it con-centrates on the most critical recent research and is ableto develop a very coherent and clearly expressedapproach to the fundamental problems of specificity inplant disease. An outside reader might well be excusedfor a certain disappointment that, in the end, the mostfundamental problems are left very much in the air,with little firmly resolved on specific molecular inter-actions. This is, of course, hardly the author's fault butwe must certainly hope that in a few years such a bookwill be able to consider successful research not only onthe mechanisms of defence but also on their control.

In the meantime, Professor Deverall's monographcan be thoroughly recommended to researchers andadvanced students in the field as a concise and criticalaccount which should help to determine good direc-tions and priorities in future work. I. M.SMITH

More Dematiaceous Hyphomycetes. By M. B. ELLts.(Commonwealth Mycological Institute: Kew, Eng-land, 1976.) Pp. 507. Price £15'00.

It seems as if it were only yesterday that the Hypho-mycetes were a comparatively unknown group of fungi,whose classification was based on archaic and primitiveprinciples. If, however, anyone still holds such views,then a brief perusal of the above book, and the sameauthor's earlier volume (Dematiaceous Hyphomycetes,1971, C.M.I.), will quickly dispel this illusion. In thesetwo books we find a breathtaking range of fantasticmicrofungi, each described in precise terms, and manyillustrated with drawings, which bring them to life in amost attractive way. In addition there is a comprehen-sive glossary, defining the terms employed, a list of thesubstrates examined, and the fungi found on each, andan index to all the specific epithets mentioned in thebook. As an encyclopaedia describing the dark Hypho-mycetes in classical taxonomic terms it is hard toimagine that this production will ever be surpassed.

My pleasure in examining, and using, this book wasdulled by only one disappointment. In the preface theauthor emphasizes the system he has adopted fornumbering the genera, which enables ready referencebetween this book and its predecessor. This is fine butwhy did such cross referencing not extend to the genericand specific keys given in More Dematiaceous Hypho-mycetes ? Indeed, it is not even obvious that the keys inthis present volume exclude genera and species which

are exclusively treated in the previous book. Hence, it isfrequently necessary to go through two keys to confirman identification. For example 15 species of Clado-sporium are keyed out in Dematiaceous Hyphomycetesand a further 28 species are described in the presentbook, being identified using a key which does not dove-tail at all into the earlier version. In some cases, it is noteven possible to use the key in one volume to narrowone's area of search in the other. The extra text involvedin comprehensive keys would have been negligible bycomparison with their value (and with the book costing£15'00 the extra pages would hardly have addedsignificantly to the cost).

The only other reservation I hold is a more generalcomment, which applies to many similar, taxonomictexts. Ecologists, physiologists and geneticists, amongstothers, appreciate first and foremost clear descriptionsof the taxa which they use or are likely to encounter.These we are normally given, and indeed they are of ahigh standard in this book. What is more often omittedis commentary on the considerations which led thetaxonomist to his decisions and on the reservationswhich he may still have about doubtful taxa. A valuableintroduction was provided in the earlier book, but thepresent volume is almost devoid of such information.I suppose we literally cannot afford to go back to theleisurely approach adopted in the early C.M.I. Myco-logical Papers, but it would be both fascinating andhelpful if we could have some more clues as to the whysand wherefores of taxonomic decisions.

The publication of this volume seems almost to markthe end of an era. Descriptive, herbarium-based,taxonomy of the Hyphomycetes, and especially thedark-pigmented genera has, in recent, years, beenbrought to a very refined state. Other taxonomictechniques must now, however, be employed to con-tinue the process of forging a classification of thesefungi which accurately reflects their natural relation-ships. More extensive cultural studies, numericaltaxonomy and chemotaxonomy will, hopefully, enableus to build on the foundations which Dr Ellis hashelped to lay in such a comprehensive and accomplishedmanner. C.H. DICKINSON

Monographie des Typhula Fr., Pistillaria Fr. et genresvoisins. By JACQUES BERTHIER. Numero special duBulletin de la Societe Linneenne de Lyon, 4Se annee,Septembre 1976. Pp. 212, figures 39, colour-plates 2.Price 100 F.

This doctoral thesis, published so excellently with fineillustrations, is a great and welcome contribution to thestudy of clavarioid fungi. Long and profound researchhas gone into its preparation, and it carries the know-ledge of these small, neglected, yet in many casesecologically and economically important, fungi farbeyond previous attainment. The author begins byexplaining the care and skill needed in the collection,culture, and microscopic study of fruit-bodies, sclerotiaand mycelia. He reviews previous classifications, per-ceives new relationships, and devises a new classifica-tion. He, then, describes about 60 species, most ofwhich he has grown in culture, arranged in four genera,