Bryophytes Hepaticae 



213 



In forms like Pellia and Aneura, it is desirable to show the sporo- 

 phyte still inclosed in the calyptra (Fig. 65). For such sections, we 

 should recommend fixing in formalin alcohol. Aqueous fixing agents 

 are likely to cause trouble on account of air bubbles. For cytological 

 studies, the calyptra must be removed and a thin slab should be 

 cut from opposite sides of the capsule to facilitate fixing and infiltra- 

 tion. Chromo-acetic acid, with the 

 addition of a little osmic acid, is 

 best for fixing. In Pellia and Con- 

 ocephalus the spores are very large 







FIG. 65. Pellia epiphylla: photo- 

 micrograph of young sporophyte at 

 the spore mother-cell stage. X21. 



FIG. 66. Pellia epiphylla: photomicro- 

 graph of spore germinating while still re- 

 tained within the capsule safranin, 

 gentian- violet. X276. 



and have a rather thin wall. Both these genera show a peculiar intra- 

 sporal development of the gametophyte,i.e., the gametophyte develops 

 to a considerable extent before it ruptures the spore wall and before it 

 is shed from the capsule (Fig. 66). Mitotic figures during the first 

 three divisions in these spores are exceptionally beautiful and are very 

 easy to stain with the safranin, gentian- violet, orange combination, 

 the chromosomes taking a very brilliant red, while the asters take 



