1917] FIELD CROPS. 141 



low as 50°. Timothy cut during the hlooming period will bloom 12 hours or 

 more after cutting, providing that the hay has not wilted. 



The color of timothy bloom varies greatly, due chiefly to the changes in the 

 color of the anther and the anther sack and the variations in the number of 

 flowers that bloom on different days. When weather conditions are favorable, 

 timothy blooming may be regarded as a continuous process to the end of the 

 blooming period, and the so-called " first " and " second " bloom, or the " blue " 

 and " gray " bloom, are misnomers. 



On the improvement of Red Olona, P. Venino {Ann. 1st. Agr. iMilari], 12 

 (1913-14), pp. 109, 110). — This is a brief note on the improvement of Red Olona 

 wheat through selection since 1910. 



The roots of zacaton and their exploitation, I. R. Martinez {La Raiz de 

 Zacaton y su Exploitacion. Mexico: Govt., 1914, pp. 26 pis. 12). — Three vari- 

 eties of zacaton are described and illustrated, namely, Festuca amplissima, 

 Muehlemhergia gracilis, and Epicanipes striata. The fiber is extracted by 

 means of a macerating machine, bleached with sulphurous acid, and classified 

 according to length and color. Directions and regulations are given regarding 

 the exploiting of the product. 



Correlation phenomena in the physical properties of grain and their prac- 

 tical significance, M. Akemine {Jour. Col. Agr. Tohoku Imp. Univ., 7 {1916), 

 No. 2, pp. 101-127). — This article is a discussion of some investigations dealing 

 with the correlations existing between certain of the physical properties of 

 the seed of rice, barley, wheat, and naked barley as to absolute weight and 

 (1) length, breadth, or thicknes^^ (2) volume, (3) size of the embryo, and (4) 

 specific gravity. The author summarizes his conclusions as follows : 



In whole ripe seed the correlation between absolute weight and length or 

 breadth is significant. In the same seeds a correlation between the absolute 

 weight and thickness is very slight, but in unripe seed such a correlation exists. 

 In whole ripe seed the correlation between absolute weight and the volume is 

 very significant. In the same seed a significant correlation exists between 

 absolute weight and the size of the embryo except in hulled rice, in which 

 case the correlation is negligible — for what reason is not yet clear. 



There is no correlation between absolute weight and specific gravity, and a 

 sorting method ba.sed on specific gravity can only be applied to the separating 

 of ripe, whole or dry seed from unripe, broken or wet seed. Seed sorting 

 based on the absolute weight by means of air currents is a theoretical cer- 

 tainty, but further improvement must be made in regulating the strength of 

 the air cu-rrent. 



A brief bibliography is given at the end of the article. 



The possibility of combating plant diseases by means of careful seed selec- 

 tion, E. Henning (K. Landtbr. Akad. Handl. ocTi Tidskr., 55 {1916), No. 4, pp. 

 282-300, fig. 1). — This is a paper presented before the Royal Agricultural 

 Academy of Sweden reviewing the history of seed control work, together with 

 the results of the more important investigations conducted from time to time 

 to increase the accuracy and reliability of seed testing. It is also pointed 

 out how various factors, especially the influences of plant diseases, may affect 

 the results of seed growth by reducing the viability below that indicated by 

 the seed examination. 



Twelfth annual report of the Canadian Seed Growers' Association for the 

 year ending March 31, 1916 {Caimd. Seed Groivers' Assoc. Ann. Rpt., 12 

 (1916), pp. 32). — A list of the operating members is given which includes the 

 kind and variety of crops grown and the number of years the seed is known 

 to have been selected. 



