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METHODS IN PLANT HISTOLOGY 
The smuts may be studied in the living material. The following 
method, described by Ellis, is worth remembering: A supply of 
smutted barley may be obtained by sowing soaked, skinned barley 
that has been plentifully covered by Ustilago spores. In such 
material it is easy to trace stages in the development of spores. 
Freehand sections of ears about 12 mm. long show the mycelium and 
spore clusters. If smutted ears be removed and kept floating on the 
water, the spores continue to develop and often germinate. For 
paraffin sections desirable stages should be fixed in Flemming’s fluid 
or picro-acetic acid. Delafield’s haematoxylin, followed by a very 
light touch of erythrosin or acid fuchsin, will give a good stain. 
For a study of the germinating spores and conidia, cultures may 
be made in beerwort on the slide or in watch crystals. Harper’s 
method of making preparations from such material is ingenious 
and is valuable in making mounts of various small plant and animal 
forms. A drop of the material is taken up with a capillary tube and 
is then gently blown out into a drop of Flemming’s weaker solution 
(15 minutes to 1 hour was sufficient for the fungus spores). Cover a 
slide with albumen fixative, as if for sections. A drop of the material, 
without previous washing, is drawn up into the capillary tube and 
touched lightly and quickly to the surface of the albumen. A series of 
such drops, almost as small as the stippled dots in a drawing, may 
be applied to the slide. The fixing agent may now be allowed to 
evaporate somewhat, but the preparation must not be allowed 
to dry. As the slide is passed rapidly through the alcohols, the 
albumen is coagulated, and the preparation may be treated just as if 
one were dealing with ribbons of sections. 
The Rusts (Uredineae). —Puccinia graminis , the common rust of 
wheat and oats, is familiar to everyone. The uredospores, or summer 
spores, known as the red rust, and the winter spores, known as the 
black rust, are found in unfortunate abundance, but the aecidium 
stage on the barberry is not necessary for the vigorous development 
of rust in the United States, and it is not nearly so prevalent as the 
red- and black-rust stages. When found, it may be so abundant that 
most of the leaves of the barberry are spotted with the cluster cups. 
It is a curious fact that wheat and oats may be quite free from the 
red and black rust in localities where the aecidium stage is very 
abundant; and that the rust stages may be most destructive where 
there are no barberry bushes. But no one doubts that the aecidium 
