Journal of Applied Microscopy. 



697 



^'>g• 33- 



only in the spring following their maturity. However, the teleutospores of many 

 species, like /'uccmia xant/iii on Xant/mim canudense (Cocklebur), will germinate 

 as soon as they ripen and will serve equally well for study. If a particularly 

 good specimen is secured, it may _^_^^=^_ 



be preserved by the method previ- II II 



ously described fordesmids, except 

 that in this case it might be worth 

 while to attempt staining with Mayer's ha^malum, or with eosin. 



The smuts may be studied in the living material. The method recently 

 described by Ellis is worth remembering.* A supply of smutted barley may be 

 obtained by sowing soaked, skinned barley that has been plentifully covered by 

 Ustila^o spores. In such material it is easy to trace stages in the development 

 of spores. Free-hand sections of ears about three-eighths of an inch long 

 show the mycelium and spore clusters. If smutted ears be removed and kept 

 floating on the water, the spores continue to develop and often germinate. For 

 paraffin sections desirable stages should be fixed in Flemming's fluid or picro- 

 aceticacid. Delafield's hematoxylin, followed by a very light touch of erythrosin 

 or acid fuchsin, will give a good stain. 



BASIDIOMYCETES. 



This is an immense group of which the mushrooms, toadstools, puffballs, 

 and bracket fungi are the most widely known representatives. 



Copri7ius comatus. — This is the common shaggy-mane mushroom 

 the cap pieces about one-fourth of an inch square, 

 and fix in chromo-acetic acid or in Flemming's fluid. 

 Portions in which the gills have just begun to turn 

 brown will show the spores still attached to the 

 sterigmata. If the gills have become dark brown 

 or black, the spores will wash ofif before the sections 

 can be mounted. Look in portions in which the 

 gills are still white or only slightly changing color 

 for the development of basidia and spores. The 

 nuclei, although rather small, are brought out 

 nicely by safranin-gentian violet-orange. The same 

 procedure may be observed for other forms of sim- 

 ilar consistency, like many members of the genera 

 Boletus, Hydfium, Polyporus, Lycoperdon, etc. 

 Leathery or woody forms like Stereum and many 

 species of J'olyporus had better be fixed in picro-acetic acid and imbedded in 

 celloidin. Young stages of Cyathus (birds-nest fungus) cut easily in parafifin, 

 but the older stages cut much better in celloidin. It is hard to get the very soft, 

 watery forms like Iremella into parafifin without shrinking, but sections as thin 

 as 10 jx may be cut in celloidin. While this is too thick to give satisfactory 

 views of such small nuclei, it brings out very clearly the general morphological 

 structures. 



Cut from 



/ 



•JOUff. APR MIC. 



s 



Kig. 34. Coprinus comatus. 

 J'ransverse section of a portion of one 

 of the gills showing a part of the 

 trama, /, and several basidia, b, 

 each with four sterigmata, s. 

 Spores have fallen off from many 

 of the sterigmata. / 750. 



* Ann. Bot. 12: 566-567, 1899. Also Jour. App. Mic. 2: 254, 1899. 



