506 



Journal of Applied Microscopy. 



METHODS IN PLANT HISTOLOGY. 



Charles J. Chamberlain. 



VII. 



In the preceding chapters the principles and methods of technique have been 

 described in a general way. It is often difficult, especially for a beginner, to 

 apply general principles to specific cases, and, besides, the types which he 



might select for the preparations might not 

 form a symmetrical collection. Conse- 

 quently, a series of forms has been selected 

 which will not merely serve for practice 

 in microscopical technique, but will also 

 furnish the student with preparations for a 

 fairly satisfactory study of plant structures 

 from the algae up to the angiosperms. It 

 is not at all our purpose to discuss general 

 morphology, but rather to answer, by means 

 of sketches and specific directions, the 

 multitudinous questions which confront the 

 instructor in the laboratory. For those 

 who have had a thorough training in gen- 

 eral morphology, the following suggestions 

 will be in some degree superfluous. Those 

 who are beginning the study of minute 

 plant structure are referred to the standard 

 text-books for descriptions of the plants 

 mentioned here. 



D 



Fig. 7. Wasser Bluethe. 



A. Ccelosph^erium Kuetzingianum. B. Anabasna 



flos-aquae. C. Anabana gigantea. D and E, a 



heterocyst and spore of A. gigantea drawn from 



paraffin sections stained in cyanin anderythrosin. 



ALGAE. 



CYANOPHYCEAE. 



1, Wasser Blilthe. — These forms occur as scums, often iridescent on the sur 

 face of stagnant or quiet water. Some of the commonest 

 forms are Coelosphaerium and Anabaena. Some of the Chlo- 

 rophyceae also occur as Wasser Bliithe. Where the material 

 is very abundant, it may be collected by simply skimming 

 it off with a wide-mouthed bottle, but where it is rather 

 scarce it is better to filter the water through a cloth, and 

 finally rinse the algai off into a bottle. Enough formalin 

 may now be added to the water in the bottle to make a two 

 per cent, solution. The material may be kept here in- 

 definitely, but after a few hours it is ready for use. If the 

 forms are small, like Anabasna, smear a slide lightly with 

 Mayer's albumen fixative, as if for paraffin sections, add a 

 drop of the material and allow it to dry, heat the slide gently 



Fig. 8. Oscillaria. 



Portions of two filaments, 

 the one at tlie right 

 showing a hormogoni- 

 uni, li. 



