1909] CURRENT LITERATURE 419 



nature of the two sexual races. From a total of 52 separate isolations, 21 were of 

 one sex, 5 of the other sex, and 26 (50 per cent.) failed to give any reaction with the 

 test strains and were listed as neutral. Three of the strains that took part in 



rmation 



format 



The distribution of the sexual races in this species is thus shown to be in accord 

 with the condition in Rhizopus, where out of 59 strains investigated by the reviewer, 

 19 were ( + ), 27 (— ), and 13 neutral. The large percentages of neutral races 

 thus established for these two species, together with the reviewer's own experience 

 with neutral races in other heterothallic species, renders it probable that sexual 

 neutrality is a widespread phenomenon among the mucors. There is little at 

 present known to indicate its cause or significance. 



Lendner, 11 in his studies of the Mucorineae of Switzerland, has not confined 

 himself to mere local species, and though he has not attempted to present an 

 exhaustive treatment of the whole group, he has given us a more or less critical 

 arrangement of the genera Mucor, Rhizopus, and Absidia. In these three genera 

 keys for the determination of species are given, and each form is described, either 

 from the original description or from A. Fischer, with additional notes on such 

 species as he had himself cultivated. In classifying the genus Mucor, Fischer's 

 division into the unbranched, racemosely branched, and cymosely branched 

 groups is followed. Fifty-one species are recognized, of which seven, M. lansan- 

 nensis, M. genevensis, M. pirelloides, M. lamprosporus, M. Jansseni, M. 

 spinescens, M. dimorphosporus, are described as new species, and one, M. adven- 

 titius var. aurantiaca, as a new variety. Bainier's genera, Parasitella and 

 Glomerula, are reduced to the genus Mucor, as also Vuillemin's Zygorhynchus. 

 The genus Mucor is the Crataegus among fungi and will probably always remain 

 a taxonomic playground for mycologists. One might imagine that early system- 

 atists used the genus as a group to practice on, and their one- or two-line descrip- 

 tions are frequently hardly sufficient to tell us whether the form described is a 

 mucor or a myxomycete. Such supposedly common 



forms 



rm 



accuracy, and therefore these designations can be considered hardly more than 

 group names. We cannot but have considerable charity toward one who feels 

 inclined, in consequence, to disregard the stock names, but when each mycologist 

 who works on the genus gets out a list with names of his own, the result is confus- 

 ing to a degree. Moreover, species shown to be distinct by the reaction between 

 their sexual strains are frequently so closely related and vary so widely under 

 different conditions of cultivation that the usual description is insufficient to 

 distinguish them. Lendner has done a service in bringing together the descrip- 

 tions of species since Fischer's publication. We are grateful that he has not 

 found it necessary to make new species out of more than 15 per cent, of the 51 forms 



" Lendner, Alf., Les Mucorine'es de la Suisse. Materiaux pour la flore crypto- 

 gamique Suisse. Vol. Ill, Fasc. I. pp. 180. 1908. 



