704 GENERAL TECHNIQUES FOR CLASSES OF PLANTS 



CiFERRi {Mycologia, xxi, 1929, p. 151) puts coverslips, coated 

 with melted agar, singly into test-tubes containing a layer of 

 cotton and filter-paper and autoclaves the tubes, which serve 

 as moist chambers. Spores are sown or mycelium is planted 

 on the coverslips. When grown, fix, stain, etc. The method is 

 especially useful for Dermatomycetes ; it is less successful with 

 fungi having erect aerial conidiophores or sporodochia. 



OvERHOTS {Proc. Int. Congr. Plant Sci., Ithaca, N.Y., ii, 1928, 

 p. 1688) describes the technique of preparing mounts of Hymeno- 

 mycetes. 



See BoYCE {Phytojmth., viii, 1918, p. 432) and Sinnott and 

 Bailey {Phytopath., xiv, 1924, p. 403) for methods of handling 

 diseased wood. 



Spores of fungi will adhere to slides if these are first smeared 

 with Mayer's albumen. Invert the slides on a suitable fixative or 

 dry and fix by heat Afterwards treat as a smear. For external 

 structure mix with balsam or glycerin jelly and cover. 



1395. Whetzel's Method for Superficial Fungi {Journ. Mycology, 

 1903). Strip off a piece of the epidermis with the superficial 

 mycelium. Simmer over a low flame in 2 to 4 per cent, caustic 

 potash for twenty to thirty minutes. Wash by standing in two 

 to three changes of water for ten to twenty minutes each. Pick 

 off the sub-epidermal tissue and if not clear again treat with 

 hot caustic potash. Dehydrate in 95 per cent, alcohol, clear and 

 mount. The host tissues are bleached, the dark hyphai and 

 reproductive bodies of the fungus not ; the method is best for 

 fungi with pigmented hyphte. Staining could be attempted. 



Abbott's Method for Superficial Fungi (Phytopath., xv, 1925, 

 p. 245). Dip a camel-hair brush into glycerin jelly and spread 

 a thin coat on a warm slide. After the jelly has hardened, press 

 the plant part bearing the superficial fungus against the jelly and 

 remove it. A large part of the fungus is left in position in the 

 glycerin jelly. 



1396. Stains. Material examined directly may be stained on 

 the slide with 0-5 per cent, aqueous eosin (followed by 2 per cent, 

 acetic acid) or with alum-eosin (0-5 per cent, of each). Filaments 

 difficult to stain will usually take Ziehl's carbol-fuchsin, as 

 prepared for bacterial purposes. Material with coloured spores 

 (Ascomycetes, Uredinales) may be counterstained with light 

 green or Delafield's hematoxylin. Spores stain well with safranin. 

 See also Hemmi and Endo, Mem. Coll. Agr. Kyoto Imp. Univ., vii, 



1928, p. 39. 



Boss {Dermatol. Wochenschr., xc, 1930, p. 482) treats a loop of 

 filamentous fungi for two minutes on the slide with a mixture of 

 10 parts of 25 per cent, antiformin and 1 part of 1 per cent, caustic 

 soda. He then fixes them with heat and stains them with Unna's 

 modification of the Unna-Pappenheim stain. 



