1910] CURRENT LITERATURE 475 
this group. The genus has been as repellent to the systematist as it has been 
attractive to the physiologist. With the exception of the work of Drerckx, 
only a brief abstract of which seems ever to have been published, there has 
been no effort to disentangle the mixture of forms of this genus. The efforts 
of THom’s toward clearing up this tangle and making possible the identification 
of forms will be welcomed, therefore, by botanists and especially by plant 
physiologists, who are now enabled to connect certain physiological activities 
with definite species. 
The plan of the work has been to carry out on different media of known 
composition series of cultures of all forms obtainable, and base the distinction 
of species upon differences in the forms and in their reaction upon the media 
under similar environment. The method is essentially that which has enabled 
bacteriologists to classify the enormous number ~ — ae which — aoa 
By this method it is shown tha 
characteristics and psig rescore, when grown on n different media. 
Species that resemble each other upon one medium show marked differences 
upon other media. The eae of the plants are constant for each medium 
upon which they are grown. The cultural work of this investigation has ex- 
tended over more than four years, and has resulted in the accumulation of 
many valuable physiological data which are conveniently tabulated at the end 
of the paper. 
In the systematic part of the work 36 species and 3 varieties are carefully 
described and their reactions upon various culture media given. these, 
13 species and 3 varieties are described as new; 9 are described under numbers 
since the author feels that their characteristics are not yet sufficiently well 
own to warrant giving them names. Camera lucida drawings showing 
the modes of branching of the conidiophores, and other diagnostic characters 
are given for 33 species and the 3 varieties. e number of species described 
probably represents a large proportion of the known species of Penicillium. 
Many of them are described as new, but it may be that of these some are 
included in the 80 odd species in the Syloge, for it is practically impossible, as 
the author has found in spite of the most painstaking attempts, to identify 
plants with older descriptions or herbarium material 
A work similar in nature, but far less in extent, was done by MANGIN™ for 
a small group of molds of ‘he genus Aspergillus. He takes up the forms con- 
fused under the name Aspergillus glaucus, securing 23 collections from various 
sources and subjecting them to comparative study under various conditions. 
Their reactions to different temperatures and to different nutrient solutions 
enabled him to separate the forms into few groups, the reactions of whose 
*THom, Cuarves, Cultural studies * species of Pencillium. Bur. Animal Ind. 
Bull. 118. pp. 109. 1910. 
%6 Manoin, L., Qu’est-ce que l’Aspergillus glaucus? Ann. Sci. Nat. Bot. IX. 
10: 303-371. figs. 15. 1909. 
. 
