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THE TWENTY-FIRST ANNUAL PLANTPATHOLOGY FIELD DAY

27 June 1947

The Twenty-first Annual Field Day was held at the School of Agriculture, UniversityCollege, Nottingham, Sutton Bonington, by permission of Prof. H. G. Robinson. Nearlyfifty members and friends attended.

The programme began at 11.30 a.m, with a demonstration of the soft-fruit plots usedin training Inspectors for the Ministry of Agriculture's Certification Schemes. Mr Martyrthen conducted the party on an interesting tour of the Horticultural Department duringwhich there was a lively discussion on some of the diseases present .

The members were the guests of the School of Agriculture at lunch. After lunch thePresident of the Society, Prof. C. G. C. Chesters, thanked Prof. Robinson and his stafffor their hospitality and for arranging a most interesting programme. In replying,Prof. Robinson outlined the developments which were taking place at the School ofAgriculture. In the afternoon Dr A. R. Wilson gave an account, illustrated by exhibits,of methods for storing potatoes which he had seen in the United States. He also discussedthe problems of potato storage under Engl ish conditions and the work that was beingdone on them.

Under the expert guidance of Mrs N. McDermott a tour was also made of the potatoplots. This proved of great interest, although it was somewhat curtailed by a thunder­storm. After tea in the Canteen most members returned to the potato plots whereDr Gregory demonstrated the results so far obtained on the spread of potato virus diseases.Members also took the opportunity of seeing other potato plots in which they wereparticularly interested . The party dispersed at about 5.30 p.m,

H. E. CROXALL

Sec. Plant Pathology Committee

REVIEW

North American Species of Mycena. By ALEXANDER H. SMITH. University ofMichigan Studies, Scientific Series, vol. XVII. (Ann Arbor, Michigan:University of Michigan Press; London: Oxford University Press,1947.) xviii +52 I pp., 56 text-figures, 99 uncoloured plates. $6.00.

With the increased use of the microscope in the study of the higher fungi ideas as to theirclassification have in recent years undergone a revolution, but are still in a state of flux.Many new genera have been established, while, on the other hand, some old genera havebeen united on the basis of microscopic characters, as, for instance, the genus Rhodophy/lus,which includes all the pink-spored Agarics with angular or nodulose spores. One of theearliest genera of Agarics to be studied microscopically was Mycena, for many species ofwhich Schroeter in 1889 described cystidia and spores. Since that time Mycena has beenthe subject of several revisions. Von Hohnel, in 1913, proposed a classification of theEuropean species based on the characters of the cystidia, and Lange (1914 and 1936)divided the section Eumycena into two groups, Ciliatae and Granulatae, according as thecystidia were smooth and more or less pointed or rounded, with spines or finger-like

352 Transactions British Mycological Societyappendages. Oort, in 1928, published a revision of the Mycenas of the Netherlands, andKuhner in 1938 produced an elaborate monograph of the European species of Mycena,in which he emphasized the importance of not only cystidia and spores but also thestructure of flesh and gills, the covering of the pileus and stem, and the iodine reactionsofboth spores and hyphae. In America Kauffman, in 1918, described cystidia and sporesfor the species of Mycena found in Michigan, and Beardslee and Coker, in 1924, gave anaccount of the Mycenas of North Carolina with drawings of microscopic detail. Between1935 and 1939 A. H. Smith published some preliminary studies of North AmericanMycenas, and this author has now completed a monograph of the North Americanspecies of the genus.

As might be expected, the North American flora is much richer in species than is theEuropean; the present work includes descriptions of 218 species, as compared with 143recognized by Kuhner for Europe. Most of the European species are found also inNorth America, but the student who is using this book, along with say Kuhner's mono­graph, may find differences of interpretation of some of the old species. Unfortunately,the older mycologists seldom thought of preserving specimens of the Agarics which theydescribed, and the descriptions alone are often insufficient to indicate precisely whichof two or more outwardly similar species was in question. Thus it comes about thatdifferent authors may interpret some of Fries's species in different senses. The specieswhich is known in this country, and to Lange, Oort and Konrad and Maublanc asMycenafilopes is described by Kuhner under the name of M. vitilis Fr., while Kuhner'sM. filopes is what these other authors call M. vitilis. Smith, in the present work, distin­guishes a species with no particular odour which he calls M.filopesfrom one with a distinctsmell of iodoform which is referred to M. iodiolens Lundell. Again, a student who is tryingto identify the common Mycena of pine woods with red-edged gills and a distinct nitroussmell would, if using either Kuhner or Smith, come to the name M. capillaripes Peck.Yet in this country this species is usually referred to M. ruhromarginata Fr., a name whichis given to a different fungus by the authors mentioned. One of the most urgent needsfor mycological nomenclature is some guidance as to the selection of type, or the methodof fixing the application of a name, in such cases as these where no authentic or typespecimen exists. If no agreement can be reached, it would be better to discard some ofthese old names, as is suggested by Smith for' Mycena chlorantha Fr.' It is a relief to findthat Dr Smith is, on the whole, conservative both in his conception of the genus and inhis interpretation of old species. For purely American species his task has been easier,since the type specimens of many of these exist and he has been able to examine them.

After an exposition of his broad concept of the genus Mycena, which includes certainspecies formerly described as Collybia or Omphalic, the author discusses in detail the variousdiagnostic characters used for species and describes his technique. Then follows anexplanation of his grouping of the species into four subgenera, and an attempt is made toplace related species together in small groups or stirpes within the adopted subgeneraand sections.

The descriptive portion of the work, which occupies pages 43-452, is provided withkeys to subgenera, sections and species, and includes full descriptions of all species knownto the author. He has also added (pages 453-470) emended descriptions of Murrill'stropical and subtropical species of Mycena and Omphalia, drawn up from examination ofthe type specimens.

Details ofmicroscopic structure are shown in line drawings, and at the end of the bookare 98 plates depicting in half-tone reproductions from photographs the habit of freshspecimens of those species known to the author at first hand. One would have preferredcoloured figures, but in these days the expense of colour printing is a limiting factor.With the help of the photographs and the microscopic characters together it should bepossible to determine any given species with some degree of certainty. The book iscompleted by a list of doubtful or excluded species and a bibliography of 12-! pages.As in other books published by the University of Michigan Press the format is good, thetext and drawings clear and easy to consult. The serious student of the genus will findthe work valuable and interesting to compare with Lange and Kuhner. Especiallyuseful are the critical observations which follow the description of each species.

E.M.W.