168 THE AMERICAN MONTHLY [Jim 



height. This plant was also common on rocks and in 

 crevices exposed to wind and sun, but was always much 

 smaller in such locations. It is evidently not a natural 

 pioneer among lichens, but grows after other plants have 

 attacked the rocky substratum, or on a thin layer of soil 

 in crevices, and best of all after trees or shrubs have 

 grown sufficiently to protect it somewhat from wind and 

 sun and have not yet become large enough or thick enough 

 to kill it out. This samu kind of ecological relation favors 

 Cladonia furcata (Huds.) Fr., a variety of which was 

 found fruiting only in such environment." 



Crown-gall — Is the name of a disease occurring at 

 the crown of many deciduous shrubs and trees particu- 

 larly troublesome to fruit trees like the pear, apple, peach, 

 prune, raspberry, cherry. Prof. J. W. Tourney who has 

 investigated the subject concludes that it is due to a slime 

 mould to which he gives the name of Dendrophagus glo- 

 bosus, which in its parasitic nature is closely allied to 

 Plasmodiophora,the fungus causing club-root, but in other 

 respects is allied to the Myxogasteres. It produces sessile 

 sporangia which occur singly or in groups of two or three, 

 one millimeter or less in diameter. The capillitum con- 

 sists of a few, thick, blunt, sparingly branched, and ir- 

 regularly nodular hollow threads ; spores orange yellow, 

 adhering in masses, smooth, galls l£-2 millimeters in di- 

 ameter are the most desirable for studying the organism. 

 The stronger Flemming's fluid was found most desirable 

 for fixing. The triple stain of safranin, gentian violet and 

 orange were most satisfactory for staining. Multinuclear 

 cells are frequently in the parenchyma cells of the dis- 

 eased area, and a new center of growing tissue originates 

 under the stimulus induced by the parasite. (Bull. Arizo- 

 na Agrl. Exp. Sta. 33.) 



Chromatophores and Nuclei of Cyanophyce^e. — In a 

 recent paper Zacharias discusses at some length the struc- 

 ture of CyauophycesB especially with reference to the 



