MYCOLOGICAL NOTES 188 
thecia had opened a eee and the asci of these had ejected 
their spores to the top of the Petri dish, where they were germi- 
nating vigorously 1 ™ the ea aren of condensed water on the = 
At this date some of the unopened perithecia were crushed i 
drop of water, so that the ascospores te liberated. The aavoetete 
thus obtained were sown on two leaves of 7. vulgare. On Aug. 5th 
one of the ae ho bore powdery Oidium-patches, while all 
the control leaves were fre 
In the second Aiea mace perithecia (just formed) were eens 
on wheat on 26 ly 80th. The leaves were placed on wet blotti 
paper, and glass slides with “ hanging drops” were suspended over 
them. On Aug. 5th these drops contained a number of ascospores 
discharged from the dehisced perithecia, and were placed on three 
leaves of seedling wheat-plants growing in a pot. The plants were 
kept under a bell-jar until Aug. 16th, when two of the inoculated 
leaves were found to bear small powdery Oidium-patches at the 
marked place where the ascospores had been sown; the control 
leaves (nine) were all free. 
n the third experiment, perithecia (just formed) were gathered 
on wheat “i July 81st. They were placed on wet blotting-paper, 
and the same method employed to catch the ascospores as in the 
second experiment. Ascospores were obtained on Aug. 11th, and 
two leaves were  frigsabae On Aug. 18th one leaf bore five small 
patches of mycelium with young conidiophores, — the “ttc leaf 
bore one similar patch ; all the control leaves rema ned fr 
It is quite likely therefore that under fa sefcere re siveteiablanel 
the species H. Graminis scl pass through its life-cycle more than 
once in the course of a yea 
With regard to the ahor species of the E'rysiphacee, however, it 
is possible that the ascospores may require a definite period of rest 
before they can germinate 
The fact that the asci of EZ. Graminis do not as a rule produce 
ascospores on the living host-plant, a remain full of living proto- 
plasm which is able to paras rm ascospores at the advent of favourable 
Saige laces EF. Graminis in a ein isolated position. 
vation res specti ng the occurrence in mid-winter of the 
sonidial (Olena stage of H. Graminis may be recorded here. At 
the end of the summer of 1902 plants of Poa pratensis growing in 
the Cambridge Botanic Garden” which were covered with large 
vigorous patches of the Oidium of E. Graminis, were dug u d 
n pots, and stood in the open. No formation of perithecia was 
observed on the leaves, and all the leaves in a few weeks died away. 
On Dec. 27th some fresh green leaves from a stolon appeared in one 
of the pots, and on one of these leaves a large well-grown patch of 
mycelium, bearing a large number of closely clustered conidiophores 
with long chains of conidia, was visible. This occurred in a spell 
of exceptionally mild weather, after some weeks of cold frosty 
° en the Cambridge University Agri- 
cultural Department, informs me that he noticed in the neighbour- 
hood of Cambridge, during the ¢ first week of December, 1902, large 
