250 BOTANICAL GAZETTE [MARCH 
Cytology of rusts.—In 1912 OLIVE” described an intermingling of perennial 
gametophytic and sporophytic mycelia of Puccinia obtegens throughout the 
n 
shoots of P. Podophyili the order is usually reversed, REE: and aecidio- 
spores appearing on the leaf sheaths, and later aecidia and spermagonia on the 
young leaves. 
The mycelium in the leaf sheath is prevailingly binucleate. In the young 
leaves the uninucleate (gametophytic) mycelium prevails, while in older leaves 
the binucleate (sporophytic) mycelium becomes predominant. The aecidio- 
spores of P. Podophylli and the uredospores of P. obtegens and Uromyces 
Glycyrrhizae are all regarded as secondary in origin and thus apogamously 
derived, arising solely from the binucleate mycelium, as the reviewer formerly 
pointed out in the first mentioned case. No sexual fusions were found in the 
young sori in which the mingled gametophytic and sporophytic mycelia occur. 
The binucleate cells of the sporophyte push in among the uninucleate hyphae 
of the gametophyte and there form spores directly. Otitve:believes this 
apogamous condition to be a result of the perennial habit. 
rmatia alone arise from the uninucleate gametophytic mycelium, 
although. binucleate hyphae often invade the immediate neighborhood of the 
spermagonia. The reviewer, being unaware of this curious mixture of the two 
kinds of mycelium, in which binucleate hyphae may become predominant, was 
led to believe the spermatia, like the apogamous aecidiospores, might arise from 
distribution were observed: (1) an unlimited growth of the perennial sporo- 
phytic mycelium alone in P. obtegens and Uromyces ae producing 
only secondary uredospores and teleutospores in confluent sori, an d (2) a 
localized distribution of the binucleate sporophytic mycelium, giving rise to 4 
sorus of teleutospores in P. Podophylli, or in the other two species to the local- 
ized “summer generation” or opiate generation,’ producing secondary 
uredospores and teleutospores.—L. HARP, 
2 OxivE, E. W., Perennial ee and sporophytic generations in P uccinia 
oblegens (Lk.) Tul. Science 35:150. 
8 OLIVE, E. W., Intermingling of Saaleica sporophytic and — ee 
tions in Puccinia Podophylli, P. obtegens, and Uromyces Glycyrrhizae Ann. Myc 
EE :207-315,. Pt. 15. 3033. 
«4 SHarp, L. W., Nuclear phenomena in Puccinia Podophylli. Bot. Gaz. 512493» 
464. Igri. 
