Thallophyta and Bryophyta 157 



Pyronema conjlneus is common on slcam-sterilized soil in the 

 greenhouse. Cytological preparations ol the sex organs are a task lor 

 the skilled investigator, and the reader is referred to the research 

 literatiue. The apothecia are processed like those of Sclcroiinia. 



Pscudopeziza medicaginis is parasitic in the leaves of alfalfa and 

 other legumes. Collect material when the pustules are just opening 

 and the apothecia are bursting through the ejMdermis. Excellent 

 preservation is obtainable with FAA, and staining presents no 

 difficulties. Even the simple hemalum stain differentiates the 

 ascospores. 



SarcoscypJia coccinea has a brilliant red, dainty, cup-like ascocarp 

 that can be killed entire and processed exactly like Sclerotinia. The 

 larger cups like those of Peziza repanda, Urmila, and the familiar 

 ascocarp of Morchella, the sponge mushroom, should be suital^ly 

 subdivided and processed as above. 



Fleshy portions of the fructifications of other Ascomycetes are 

 handled like the foregoing types. Interesting slides are obtainable 

 from Hypojnyces, a parasite on mushrooms; Cordyceps, parasitic on 

 insects; the fruiting head of Claviceps, the ergot fungus; the 

 saprophytic Neurospora. Species of Nectria in which the stroma is 

 moderately soft can be sectioned. Remove the stroma down to the 

 wood, subdivide vertically into narrow strips, kill in FAA or Craf II, 

 and process in TBA. Always examine freehand sections or smears of 

 fleshy Ascomycetes to determine whether the desired stage of ascus 

 formation is present. 



In the Taphrinales (Exoascales) only the genus Taphrina 

 (Exoascus) is of importance. Taphrina deformans, the casual organism 

 of peach leaf curl, is very abtmdant in some localities. The malformed 

 succulent leaves are Avell preserved by Bouin's solution or Craf II. 

 Sectioning and staining present no difficulties. 



Ventiiria inaequalis, the apple scab organism, is widely distributed 

 and easily obtainable in the conidial stage on the leaf. A vigorous 

 fluid like FAA or Craf V is necessary. A simple stain such as hemalum- 

 safranin is adequate. The perithecia mature in early spring on last 

 year's decayed leaves. Such material can be studied well from newly 

 gathered soaked leaves or bulk-preserved leaves. Such material yields 

 permanent slides of decidedly ragged appearance, and microtoming is 

 therefore to be discouraged. 



BASIDIOMYCETES 



This group contains a great diversity of forms and involves a wide 

 range of techniques. We are again confronted with saprophytes that 



