64 The American Naturalist. [January, 



ent media, the best results being obtained from the following : fresh, 

 damp horse dung ; dung decoction ; agar-agar with 2} per cent pep- 

 tone ; agar-agar with 4 per cent peptone and 0.5 per cent nitrate of pot- 

 ash. (2) End sporangia present ; sporangiola 16-60 ft in diameter, 

 with numerous spores and frequently with a columella and partial 

 swelling up of the membrane. This type was obtained in nine differ- 

 ent media, including the following : thoroughly cooked plums ; damp 

 bread ; eggs ; oranges ; malt. (3) Only the end sporangium present. 

 Obtained on slightly cooked plums and on 1 volume of malt extract 

 in 2 vol. water. (4) Only the sporangiola present. Obtained in vari- 

 ous culture media by raising the temperature to 27-30° C. (5) a. 

 Mycelium with thick ends and gemma?. This form was obtained in 

 the following media : plum decoction with peptone ; 1 vol. grape must 

 in 4 vol. water with peptone ; 1 vol. malt extract in \ vol. water, b. 

 Mycelium with fine ends and without gemmse. Obtained in the fol- 

 lowing fluids : 1 per cent nitrate of potash with 1 per cent Nahrlos. 

 ung; almond oil with Niihrl.'isun^ ; oleic acid with NTihrlosung ; cane 

 sugar in various percents. (6) Formation of zygospores. Not ob- 

 served. According to the author, Th. elegans is the only fungus 

 known which can be induced to form this or that sporangium, or none 

 at all, by means of purely external, known conditions. He believes 

 the production of the first type is due to substrata in which nitrogen- 

 ous substances preponderate and fats and carbohydrates are present 

 in only small quantities, and that the second type is due to the reverse 

 of these conditions. The paper contains 24 pages and is illustrated by 

 a double plate.— Erwin F. Smith. 



Germination of Refractory Spores.— In spite of every effort, it 

 occasionally happens that the spores of a fungus refuse to germinate 

 either in water or artificial media. This is true of various oospores, 

 teleutospores and ascospores, and particularly and notably of the basi- 

 diospores of the whole group of the Gastromycetes, scarcely anything 

 being known of the early stages of species of this group, owing to this 

 fact. Recently, Dr. Jacob Eriksson, of Stockholm, has tried cold on a 

 number of uredospores and secidiospores with partial success. His 

 method consists in placing the spores for several hours on blocks of ice 

 or in a refrigerator at temperatures ranging down to minus 10° C. In 

 a number of instances spores which refused to germinate in water at 

 room temperatures, either wholly or in great part, did so freely and 

 speedily after being on ice or in a refrigerator. In other cases the 

 cold appeared harmful or without sensible influence, even on the same 

 species. The opinion has been current for a long time that sudden great 



