372 BOTANICAL GAZETTE [APRIL 
until the plants have reached a more advanced state of development. In gen- 
eral, the production of teleutospores appears to be associated with the depletion 
of the carbohydrates of the leaves. A direct influence of climatic or seasonal 
factors does not appear to exist. 
DreTEL,® in the third instalment of his studies on the conditions affecting 
e germination of teleutospores, reports that the teleutospores of Puccinia 
ae germinate and form sporidia only in a saturated atmosphere. 
the degree of saturation is only slightly below roo per cent, normal germina- 
tion does not take place. Furthermore, germination takes place only when 
water is abundantly supplied through the pedicels. When leaves of Althea 
rosea bearing rust sori were suspended in a saturated atmosphere in a bottle, 
but with the stems projecting into the air through the cork, no germination 
took place, although the leaves remained turgid. When the petioles were 1m- 
mersed in water, germination of the teleutospores in the sori began immediately. 
The author’s interpretation of these observations is that the water necessary 
for germination is supplied to the teleutospores through the pedicels, but that 
an adequate supply is possible only under conditions of complete turgor of the 
host, and in a saturated atmosphere. The sporidia of Puccinia Malvacearum, 
it was noted, lose their vitality in one hour in an atmosphere of go per cent 
saturation, and in 10-16 hours even in a saturated atmosphere. 
An unusual case of mycelial distribution is reported by FiscHER™ for 
Puccinia Dubyi. The Seyeemn ue come aiomamana is — strictly localized, 
but in P. Dubyi Fr the older infected 
leaves of the host (Androsace) through the stems to the newly formed whorls 
where new sori are produced. Instead of one crop of teleutospores usual in 
micropuccinias, this form produces a succession of sori through the season oO 
FRoMME'S reports that the germ tubes of the uredospores of Puccinid 
Rhamni are negatively geotropic, and that as a rule the germ tubes grow out 
from the pores on the non-illuminated side of the spore. Of 200 germ tubes 
issuing from spores illuminated on one side, 86 per cent had grown away from 
the light. The germ tubes of spores in darkness grew equally well in all 
directions. This Pike of the germ tubes undoubtedly is of significance in 
the process of infec 
Remarkable ce changes in Puccinia Ellisiana and P. Andropo- 
gonis due to the influence of the host have been reported by Lone."® Both of 
13 DIETEL, P., Versuche iiber a a der Teleutosporen einiger 
Uredineen III. Centralb. Bakt. Il. 42:698-705. 19 
“4 FISCHER, E., Beitrage zur Biologie der ea 6. Mycol. Centralb. 5:1137 
IIQ. 1914. 
*s Fromme, F. D., Negative heliotropism of urediniospore germ tubes. Amer. 
Jour. Bot. 2:82-85. tas. 2. I915. 
G, W. H., Influence of the host on the morphological characters of Puccinia 
_Ellisiana pa fae Anarsstavels. Jour. Agric. Research 2:303-319. 1914. 
