1900] MICROSCOPICAL JOURNAL _l8d 



some writers to have centrosomes,Strasburger states that 

 these granules are not centrosomes, but that the spindle 

 often reaches to and ends on the peripheral layer of the 

 cytoplasm in multipolar way. The blepharoplastsare but 

 remotely related to them. 



Fungi and Humus. — According to F. Reinitzer (Bot. 

 Zeit. 58 : Abt. 1.59) humus is not a favorable medium for 

 the growth of saphrophytic fungi. In the experiments 

 made by Reinitzer the soluble matter was removed. It 

 was found that such fungi as Penicllium glaucum, Botry- 

 tis cinerea did not grow or only with difficulty. The hu- 

 mus consists of waxy aldehydes. These experiments con- 

 firm those of other investigations that humus is not food 

 for plants. 



Leaf Scorch. — According to F. C. Stewart, Leaf Scorch 

 is a physiological disease. Whenever the quantity of 

 water transpired by the disease is greater than the roots 

 are able to supply, leaf scorch occurs. The factors enter- 

 ing into this problem are the area of leaf surface, expo- 

 sure, quantity of water in the soil, activity of the roots, 

 the location of the trees as exposure to wind. M. Stewart 

 records that Grleditschia triacanthos, hicory, sugar beets, 

 cherries, and maples were affected by this disease. 



Red Color in Plants. — The recent researches of Over- 

 ton on the red cell-sap of plants shows that its occurrence 

 is conditioned upon the presence of sugar, and that the 

 depth of the tints depends upon the concentration of su- 

 gar. Low night temperatures induce the development 

 of such colors, whicli the author believes accounts for the 

 reddish coloration of alpine species and to the same cause 

 are due the yellowish-red tints of evergreen leaves dur- 

 ing the winter. If two plants of the ordinary bladder- 

 wort (Utricularia) are grown in separate dishes of water 

 containing different proportions of sugar, the relation of 

 this substance to color production can be verified. — 

 (Journal N. Y., Botanical Grarden). 



