226 ELEMENTS OF BOTANY 
spores appear, produced from the same mycelium. This growth is 
chiefly upon the stems and sheaths. 
289. Cluster-Cup Stage. — Note with the naked eye and with a 
magnifying glass the appearance of the cluster-cups wpon the bar- 
berry leaf. Fresh specimens should be used if available. Note 
whether the leaf is changed in form or color in any part occupied 
by the fungus. Note the number of cups in a cluster, the position 
on the leaf (which surface’), the form and size, especially the height. 
Are they straight or curved? Describe the margin of the cup, the 
color without, and the color of the contents. 
With a power of 200 diameters or more examine some of the 
cells composing the cup and note the form, color, and nature of the 
surface. Draw. With the point of a needle or kuife pick out a bit of 
the contents of the cwp and examine as above. Note the characters 
as before and compare in detail with the cells of the cup. The cells 
within the cup are the spores. Can you tell how they are attached? 
Fic. 161. A Cluster-Cup of Anemone Rust (Puccinia fusca). (x 120.) 
s, chains of spores; p, the covering or peridium of the cup; h, hyphie. 
A thin section through the cup will show the mode of attachment 
and the relation of the spores to the cup. 
290. Examination of Red and Black Rust. — Under the magnifying 
glass examine the eruptions of spores (sor7) on the wheat plant, some 
of red spores and some of black spores. The red spores are faded in 
dried specimens. Note the approximate size and shape and any 
other peculiarities. Prepare slides of each kind of spores and see if 
