Eumyeetes. 
469 
Diatrypelle favacea. Ausserdem giebt der Herausgeber auch sehr 
willkommene Supplemente zu früher ausgegebenen Arten. 
Die Exemplare sind wieder reichlich, sorgfältig ausgesucht und 
genau bestimmt. Auf den Zetteln sind wieder die älteste Veröffent¬ 
lichung des Namens, die wichtigste Synonymik mit genauer Quellen¬ 
angabe. Standorte und Datum genau angegeben. 
P. Magnus (Berlin). 
Kauffman, C. H., A Contribution to the Physiology of the 
Saprolegniaceae, with special reference to the variations of 
the sexual organs. (Annals of Botany. XXII. p. 361—387. with 1 
plate. 1908.) 
The author has applied the cultural methods, which Klebs used 
for a single species, for the purpose of a comparative study of a 
number of species. The relation of special cultural conditions to 
antheridial development was studied in particular and also the va¬ 
riations of those characters which are used as diagnostic ones. The 
author gives a full account of the technique used and describes a 
method of obtaining pure cultures from a single zoospore. He veri- 
fies by the study of various forms the work of Klebs on S. mixta 
as to the effect of nutrition on the differentiation of the vegetative 
and reproductive processes. Not all the species of Saprolegnia pro- 
duce sexual organs under the conditions favourable to those of S. 
mixta and S. hypogyna and they are, therefore, physiologically as 
well as morphologically distinct. S. hypogyna which has morphologi- 
cally no true antheridia, can be made to develop these organs 
under suitable nutritive conditions, e. g. by the addition of K 3 P0 4 , 
KN0 3 , Ca(N0 3 ) 2 , etc. to haemoglobin solution. The antheridial fila- 
ments arise in either a diclinous or an androgynous way in all,the 
species examined under varying conditions of culture, so that their 
mode of origin is of no special importance as a diagnostic character. It 
was found also that nearly all the characters used for diagnostic 
purposes were also variable. This raises the question of the Varia¬ 
tion, mutation and constancy of species in the group. These points 
are discussed by the author who is led to the conclusion „that there 
are a great many simple forms — elementary species in the sense 
of de Vries — within the genus Saprolegnia .” The only satisfactory 
way to monograph this family would seem to be one which refer- 
red” all the species to definite conditions which should be uniform 
for all, and to determine in each the variability to the extreme 
attainable limits; we should then have attached to each description 
of a species an account of its variabilities.” The author adds that 
such a physiological basis for species seems to be the only starting 
point in a revision of the relationship of the species of any family 
of plants. The author considers that his observations on the anthe¬ 
ridial development, though not conclusive, support the view that 
sex in plants is determinable by external conditions. 
V. H. Blackman. 
Neger, F. W„ Ein Infectionsversuch mit Peridermium Strobi 
von Pinus monticola. (Naturw. Zeitschr. f. Land- und Forstw. 
VI, p. 605—606. 1908.) 
Es wurde beobachtet dass durch Blasenrost auf Pinns monticola 
von verschiedenen i?/Ö£sarten nur eine, nämlich R. sanguineum 
befallen wurde, während R. alpinnm, R. rubrum, R. aureum und 
