196 Journal of Mycology [Vol. 8 
cereale und Avena sativa) ; P. triticina auf Triticum vulgare 
(und Secale cereale) ; P. bromina auf Bromus mollis, B. arvensis 
etc. (und Secale cereale) ; und P. agropyrina auf Triticum 
repens (Secale cereale und Bromus arvensis). Zu derselben 
Kategorie ware auch in Folge des oben mitgeteilten P. Phlei- 
pratensis auf Phleum pratense, Festuca elatior (Phleum michelii, 
Avena sativa und Secale cereale) zu rechnen.” Referring again 
to the peculiarities of this species the following conclusion is 
recorded, namely, that perhaps “P. phlei—pratensis urspriing- 
lich aus P. graminis entstanden sei, und dass sie sich allmahlich 
auf dem seit langer Zeit im Grossen gebauten gewohnlichen 
Timotheengrase zu einer selbstandigen Art differenziert habe, 
selbstandig insofern, dass sie die urspriingliche aecidienerzeu- 
gende Fahigkeit verloren, die innere Natur jedoch so beibehalten 
habe, dass sie, wenn auch schwierig, auf den Hafer und Roggen 
zurukgehen kann. Weniger vorgeschritten aber denke man sich 
die Differenzierung an den seltenen, nur zufallig in den botan- 
ischen Garten kultivierten Phleum-Arten, welche durch daneben 
angebauten Getreide direkt angesteckt worden sind. Der Pilz 
hat hier keine Gelegenheit gehabt, sich Generation nach Genera¬ 
tion zu einer Form mit specifischen Eigenschaften herauszubilden 
und zu fixieren.” 
Binucleate cells in certain Hymenomycetes is the title 
of an important article in the January No. of the Botanical Ga¬ 
zette (33 '.1-25, pi. 1, January, 1902), by Robert A. Harper, which 
from its length can not be here properly summarized. Two sen¬ 
tences however may be quoted. “It must not be assumed without 
further evidence that the Rusts are primitive Basidiomycetes.” . . 
“The binucleate condition of the hyphal cells suggests very 
strongly that Rusts and Basidiomycetes must have arisen from 
some ancestral type characterized, at least in some stage of its 
development, by the possession of binucleate instead of uninuc- 
leated or multinucleated vegetative cells.” 
A very interesting and important preliminary report of 
work done during the last two years by John L. Sheldon, at 
the University of Nebraska, in co-operation with the U. S. Dept, 
of Agr., on the Rusts of Asparagus and Carnation—and inci¬ 
dentally on Darluca—is given in Science, N. S. 16:235-7. 8 
Aug. 1902. The account pertains to inoculation experiments. 
The period of incubation in the greenhouse varied from 18 to 
8 days. “When the mean daily temperature in the greenhouse 
was 69° and the average hours of sunshine were five, it required 
fourteen days for the sori to appear after an inoculation was 
made; and when the temperature increased to 76° and the num¬ 
ber of hours of sunshine increased to 6.3, only eight days were 
required; the period of incubation being in each case inversely 
as the temperature and the hours of sunshine.” Only vigorous 
