FUNGI 
225 
corrosive sublimate and acetic acid, rinse in 50 per cent alcohol, 
then treat with 10 per cent hydrofluoric acid in 50 per cent alcohol, 
wash in two or three changes of 50 per cent alcohol. In either case, 
imbed in paraffin. Cut about 5 n in thickness and stain in iron-alum 
haematoxylin. A rather strong stain of orange in clove oil will 
make it easier to trace the mycelium in the host. Uredospores and 
teleutospores, both young and old, are shown in Figure 62. 
Various stages in the germination of the teleutospores of Gymno- 
sporangium are shown in Figure 63. Reduction of chromosomes takes 
place at the first two divisions of the nucleus in the basidium. The 
sterigmata in this species are very large. 
The Fleshy Fungi.—-For habit study, nothing is equal to fresh 
material; for second choice, buy canned “mushrooms” (usually 
Agaricus campestris) at the grocery; forms not readily available in 
field or grocery may be preserved in formalin alcohol (6 c. c. of formalin 
to 100 c.c. of 50 per cent alcohol). When formalin is used in water, 
the fungi become too soft. Larger forms of the mushroom, puff¬ 
ball, and bracket types may be dried in an oven. The circulation of 
air should be good and the temperature should be kept at about 50° C. 
After drying, the fungi should be poisoned. 
For sections, Gilson’s fluid deserves more recognition than it has 
received. It is particularly good for soft forms, like Tremella. 
Gilson’s Fluid.— 
95 per cent alcohol. 42 c.c. 
Water. 60 c.c. 
Glacial acetic acid. 18 c.c. 
Concentrated nitric acid. 2 c.c. 
Corrosive sublimate (saturated solution in water).. 11 c.c. 
Fix about 24 hours and wash in 60 or 70 per cent alcohol. 
Coprinus micaceus is particularly good for a study of gills, basidia, 
and the formation of basidiospores, because it is so small that a single 
section may show a fine series of stages. Gills which are becoming 
brownish at the tip, but which are still white toward the top of the 
cap, will show a splendid series of stages. For fixing, cut out pieces 
of the gills 1 cm. long and 3 mm. thick. Such material fixes well in 
Flemming’s weaker solution. Cut paraffin sections perpendicu¬ 
lar to the gills. To show the four basidiospores, sections should 
