FUNGI 



259 



To obtain the spore stage, put a cake of good yeast, free from bac- 

 teria, into equal parts of grape juice and distilled water; add 1 g. of 

 peptone and allow to bud freely overnight at 30° C. ; place the material 

 in a plaster-of-Paris cup with a 

 depression, and put the cup in a 

 small Stender dish with water 

 coming nearly to the top of the 

 cup. In 60-70 hours there should 

 be abundant spore formation. 



ASCOMYCETES 



This group, popularly known 

 as the "sac fungi," contains an 

 immense number of saprophytic 

 and parasitic forms. The green 

 mold on cheese and leather, the 

 leaf curl of peach, the black knot 

 of cherry and plum, and the 

 powdery mildews are familiar to 

 everyone. The few objects select- 

 ed will enable the student to ex- 

 periment, but he must not be 

 discouraged if success does not 

 crown the first attempt, for some 

 members of the group present 

 real difficulties. 



Peziza. — The Pezizas and re- 

 lated forms are fleshy and pre- 

 sent but little difficulty in fixing, 

 cutting, or staining. They are 

 abundant in moist places, on de- 

 caying wood, or on the ground. 

 The apothecia have the form of little cups, which are sometimes black 

 and sometimes flesh-colored, but often orange, red, or green. 



For general morphological work it is better to tease out fresh or 

 preserved material. The best views for the beginner are obtained in 

 this way (Fig. 67). 



For the free nuclear division in the ascus, the Chicago chromo- 

 acetic-osmic formula is excellent. Fix for 24 hours and stain in 



B 



Fig. 67. — Peziza: A, several specimens grow- 

 ing on rotten wood, natural size. B, several ma- 

 ture asci, each with 8 ascospores; some young asci 

 near the base; and some long slender paraphyses. 

 Teased and mounted whole. X 230. From Cham- 

 berlain's Elements of Plant Science (McGraw-HiU 

 Book Co., New York). 



