FUNGI 



269 



worth while to attempt staining with Mayer's haem-ahim or with 

 eosin. 



Gymnosporangium, which is rather common on Juniperus virginiana 

 (red cedar), forms its basidia in the "cedar-apple" stage. Bring the 

 cedar apples into the laboratory in late winter or early spring and put 

 some into a dish of water. The yellowish, gelatinous strands with the 

 germinating teliospores may appear within 24 hours. The various 

 stages are easily recognized under a low-power dry lens without even 



Fig. 73. — Gymnosporangium: A, beginning of germination of teliospore. B, later stages, the 

 lower basidium showing the nucleus in the synapsis stage of the heterotypic mitosis, and the upper 

 basidium showing the four-cell stage following the homotypic mitosis. C, the two figures of the 

 homotypic mitosis; D, E, F, and G, later stages showing the formation of basidiospores, many of the 

 basidiospores being binucleate — g, gelatinous stalk; 6, basidiospore; s, sterigma. Fixed in 10 per 

 cent formalin and stained in iron-alum haematoxylin. XSOO. 



crushing the gelatinous masses. The teliospores germinate readily and 

 one soon gets the stages shown in Figure 73. The basidiospores may be 

 germinated on apple seedlings (the Jonathan apple is particularly 

 good), and aecium stages may be obtained in this way. 



Fix in 10 per cent formalin for 2 or 3 days. If any acetic acid is used 

 in the formula, the soft, gelatinous material is dissolved, and the 

 material goes to pieces. In chromic fixing agents, the material also 

 breaks up. In germinating stages, however, the basidia, in which re- 

 duction of chromosomes takes place, can be seen. One of the soft, 



