ELEMENTS OF BOTANY 
bo 
te 
iNe 
Sow some of these spores on the surface of “hay-tea,” made by 
boiling a handful of hay in just water enough to cover it and then 
straining through cloth or filtering through a paper filter. After 
from three to six hours exam- 
ine a drop from the surface of 
the liquid with a medium 
power of the microscope (half- 
inch objective) to see how the 
development of hyphe from 
the spores begins. Sketch. 
After about twenty-four 
hours examine another por- 
tion of the mold from the sur- 
face of the liquid and study 
the more fully developed 
mycelium. Sketch. 
287. Zygospores.— Besides 
the spores just studied, zygo- 
spores are formed by conjuga- 
tion of the hyphz of the black 
molds. It is not very easy to 
find these in process of forma- 
tion, but the student may be 
able to gather from Fig. 159 
the nature of the process by 
which they are formed, 
process which cannot fail to 
a 
Fic. 159. Formation of Zygospores 
in a Mold (Mucor Mucedo). 
remind him of the conjuga- 
tion of pond-scum. 
1, threads in contact previous to conjuga- 
tion; 2, cutting off of the conjugating 
cells a from the threads b; 3, a later THE STUDY OF WHEAT 
stage of the process; 4, ripe zygospore; >TTamN 
5, Saunas of a ed nae Bue 
formation of a spore-case. (1-4 mag- 
nified 225 diameters; 5 magnified about 
60 diameters.) 
(PUCCINIA GRAMINIS) 
288. Occurrence. — Wheat 
rust is common on cultivated 
wheat and other grains, and also on many wild and cultivated forage 
grasses. In fact, this or similar rusts occur on a very large number 
