534 BOTANICAL GAZETTE [jitne 



gave no osazone reaction. The dextrine thus obtained is strongly reducing 

 to Fehling's solution, and is considered by the authors as the end dextrine of 

 cellulose. Diastase will not split cellulose dextrine. They also derived 

 zellobiose by the Madsen method. The contents of the first stomach of 

 cattle, the intestine, and the pancreas bore no enzyme that would split zello- 

 biose. They conclude that the splitting of this substance in the alimentary 

 canal of the cattle must be due to cellulose bacteria. — Wm. Crocker. 



Ecological diversity and generic coefficients. — The principle first enunci- 

 ated by Jaccard, and noted in this journal," that the ratio between species 

 and genera, or the generic coefficients, varies inversely with the diversity of 

 the habitat conditions, has received additional support from the investiga- 

 tions of Dufrenoy 12 upon the distribution of parasitic fungi in different 

 habitats. Diversity of ecological conditions was found at altitudes of noo m. 

 to 2000 m. in the valley of Bareges, where the generic coefficient for rusts was 

 20 per cent and for all fungi 40 per cent. Contrasted with this were the 

 uniform conditions in a wheat field showing generic coefficients for its fungi of 

 70 per cent, and upon sand dunes with coefficients ranging from 90 to 100 per 



cent. — Geo. D. Fuller. 



Lignins. — Pringsheim and Magnus, 13 in a study of lignins, have obtained 

 some interesting results. When wood or straw is treated with sodium hydrate 

 in the cold, all the acetic acid liberated is derived from the lignins of these 

 materials. When these materials are boiled with sodium hydrate, either 

 under pressure or otherwise, most of the acetic acid formed is derived from 

 the lignins; but a small part is derived from the cellulose and none from the 

 pentoses. The lignin of the white beech yields about 37.85 per cent of its 

 weight of acetic acid, and the lignin of conifer wood about 19.48 per cent. 

 Wm. Crocker. 



* 



Dioecism in Thalictrum. — Schaffner 14 has studied Thalictrum dasycarpum 

 in reference to intergrades between the monoecious and dioecious condition. 

 It seems to be a peculiarly favorable form for this purpose, and almost every 

 conceivable intermediate in the expression of "maleness" and "femaleness" 

 was found. The author rightly calls attention to the fact that the physiological 

 and ecological factors concerned in these various expressions must be taken 

 into consideration for an understanding of the evolutionary changes leading 

 from the bisporangiate to the monosporangiate condition. — J. M. C 



11 Bot. Gaz. 57:540. 1914. 



12 Dufrenoy, J., Diversite ecologique et coefficients gendriques. Bull. Trim. Soc. 

 Mycol.Fr. 35:27-46. 1919. 



13 Pringsheim, H., and Magnus, H., tJber den Acetylgehalt des Lignins. Hoppe- 

 Seyler Zeit. Physiol. Chem. 105:179-186. 1919. 



* Schaffner, J. H., Dioeciousness in Thalictrum dasycarpum. Ohio Jour. Sci. 

 20- 2 5-34. I9J9- 



