FIELD CROPS. 829 



of the parents in the Fi of the cross, the leaves of the cross tending to be longer, 

 narrower, and to possess a greater number of segments than the mean between 

 the parents or than either of the parents themselves. In other words, the 

 crosses tend to be more vigorous than the parent plants. The combination of 

 the same two characters in different crosses may or may not produce the same 

 results in the Fi of the crosses, while reciprocal crosses frequently differ in the 

 young plants, but more rarely in the old plants, in respect to the heredity of 

 characters of size, shape, and number. The size and probably the shape of 

 the seed of the female parent is found to produce an effect on the heredity of 

 size and shape, in the Fi, of the cotyledons, which may or may not extend to 

 the first leaves. The dwarfs react in the character of size in the Fi crosses, as 

 if they had larger cotyledons. 



The infection of root hairs by means of Bacillus radicicola, E. B. Fred 

 (Virginia Sta. Rpts. 1909-10, pp. 123-137, figs. 86).— A description is given of 

 the method of infection of leguminous plants by B. radicicola, the author 

 showing that after entrance is gained into the root hair the tubercle bacteria 

 multiply rapidly, forming a thread-like growth from the point of infection 

 along the hair into the inner cells. The course of infection is not marked by 

 a well-defined tube, as some authors have described, but by the infecting 

 strand in which the separate bacteria can be distinguished. The course of 

 infection is generally along the center of the root. Soon after infection a 

 conical mass of cells is formed, which develops into the tubercle and pushes 

 out the overlying cortical parenchyma and epidermis. Though the cortical cells 

 are somewhat compressed, the epidermis is not ruptured nor does the tubercle 

 burst out of the side of the root. Older tubercles sometimes appear as though 

 formed exogenously, but if their development is carefully traced it will be 

 found that they were formed endogeuously; 



Studies were made of 4 separate species of leguminous plants to determine 

 the variation in the shape and size of the bacteroids. These forms are de- 

 scribed, and the author considers them stages in the development of the bac- 

 teria and not degeneration nor transformation forms. In the development of 

 the bacteroids the author noticed that certain poi'tions were not stained by 

 the ordinary methods and these are considered as being vacuoles. This is also 

 believed to be a definite period of growth and not a sign of polymorphism of 

 the bacteroid. 



The plants representing different periods of growth as well as the organism 

 causing the root tubercles are figured and described. 



FIELD CROPS. 



[Pield crops experiments in Alaska], C. C. Geoegeson et ax. (Alaska Stas. 

 Rpt. 1910, pp. 1-^-16, 31-33, 36-40, U-49, 50-52, 51,-58, 62, 68, pis. 9).— At the 

 Sitka and Rampart stations sprouted potatoes yielded much more abundantly 

 than those not sprouted. At the Rampart Station the 6 best varieties are the 

 following : Extra Early Triumph, Extra Early Eureka, Extra Early Pioneer, 

 Gold Coin, Irish Cobbler, and Early Ohio. At the Fairbanks Station 11 acres 

 were planted to potatoes but only 3i acres, on newly cleared birch land on a 

 hillside with a southern exposure, gave satisfactory yields. The 3 varieties 

 giving the highest yields are Eureka, Gold Coin, and Red Early Ohio. Gold 

 Coin is mentioned as among the highest yielding varieties at all these stations. 



At the Rampart Station attempts are being made to secure an earlier and 

 higher yielding barley by crossing. Kharkov winter wheat came through the 

 winter with a 90 per cent stand and matured a fair crop. All the varieties of 

 winter rye so far tried have lived through the winter and matured grain, but 



