210 



Methods in Plant Histology 



also the various cell contents (Fig. 61). The chloroplasts and leuco- 

 plasts are well differentiated by this stain. After corrosive sublimate- 

 acetic, a vigorous staining in a mixture of acid fuchsin and iodine 

 green often brings out the walls very sharply. After corrosive 

 sublimate-acetic the material may be stained in bulk with alum 

 cochineal or alum carmine, thus giving fairly good preparations 

 and saving considerable labor. 



Antheridia. -It is not difficult to get good preparations showing 

 the development of antheridia. In forms like Conocephalus, Asterella, 



FIG. 62. Marchantia polymorpha: early stages in the development of antheridia; 

 from an unpublished drawing by Dr. W. J. G. Land. X600. 



Pellia, etc., cut out small portions of the thallus bearing the anther- 

 idia. The piece should not be more than 1 cm. long and 5 mm. wide, 

 preferably smaller. For the development of the antheridra of Mar- 

 chantia, select young antheridiophores which still lie close to the thallus. 

 With the antheridiophore, cut out a small piece of the thallus, about 

 5 mm. in length. For general development, cut 10 ju, but for details 

 of spermatogenesis, sections should not be thicker than 3 p (Fig. 62) . 

 If antherozoids are found escaping, transfer them to a small drop 

 of water on a clean slide, invert the drop over a 1 per cent solution 





