139 
ing temperature there is no 0 change in the size or ~~ of 
conidia. Cultures which roduced microconidia in pro- 
The factor cf temperature, therefore, like those of light a nd 
humidity is not the determining condition in the fortixtion- of 
microconidia 
Nuatrition.—The factor oa ached is much more complex than 
the three factors on have been briefly commented upon. Many 
distinct influences are com enc such for example as the 
physiological avedlability of the nutritive substance and its 
accessibility to the fungus, the dilution or concentration i Hy 
© 
B 
Ru 
5 
6 
o 
nD 
mn 
3 
5 
- 
th 
aS 
mn 
. Failure to resets seh beteen thes 
component factors renders invalid the results obtai in perhaps 
the majority of investigations on the nutrition of fun 
The substrata on which microsporogeny has bedtierél in the 
present work saietw the following :—Potato agar, potato gela- 
tine, parsnip agar, parsnip gelatine, Quaker oat agar, Quaker oat 
gelatine, steamed slants of tuber of potato and artichoke; roots 
of red beet, sugar beet, carrot, turnip, and swede ; fruits of 
lations into the following living hosts have given microco- 
f daffodil, and onion; fruits of apple, pear, 
quince, and tomato; roots of beet, sugar beet, carrot, sw 
and turnip; and tubers of potato and artichoke. penta! Cale op 
has been observed on the following naturally infected hos 
Bulbs of onion and hyacinth, a s of apple, tomato, and wera 
leaves of cabbage, densutte cotyledon, clematis, geranium, and 
other herbaceous plants, and ne of carrot. It may also conve- 
niently be noted here that strains of Botrytis derieea from the 
following original hosts have produced microconidia in culture 
0, 
r 
primula, shoots and ‘“‘fruits” of fig trees, ada “the st ee of 3 an 
Aesculus rae which had bas killed by the fun 
authors have oe bel cay upon peptone, a tlled ‘water, 
but in the present coal this hypothesis is very improbable, 
for, as noted above, microconidia occur regularly on all kinds 
media and natural hosts under perfectly normal conditions, oak 
possess a well-defined bi bea in the life- -cycle of the fungus. © 
F rogeny is a ap pein or be 
ound 
* Since sg hae was written microconidia have been found in strains of 
the fungus derived from thirty additional hosts, and have incurred im 
are on all I the media and natural substrata 
+ See Worsdell, W. C.: Principles of Plant Teratology, London, 1915. 
