FIELD CROPS. 633 



with long internodes. Long internodes were dominant to sliort ones, and late 

 flowering to early. It is stated that attention should be given to these facts in 

 crossing varieties of peas. 



The nature of the influence in inducing precosity of flowering and physio- 

 logical problems attending the phenomena are not discussed. 



Studies in the inheritance of doubleness in flowers, E. R. Saunders {Jour. 

 Oenetics, 1 (1910), No. 1, pp. 57-69, figs. 7). — Studies were made with several 

 species and garden varieties of petunias to determine the phenomena connected 

 with doubling of flowers. 



Single petunias belonging to the forms used, whether self-fertilized or 

 crossed with each other, yielded singles. Cross-bred singles derived from one 

 single and one double flowered parent produced singles when self-fertilized or 

 fertilized among themselves. Singles crossed with pollen from a double 

 yielded doubles in the first generation, and there was some evidence to show 

 that this was in a constant ratio. The stamens in the double flowers were 

 found to be functional, but the pistil was more or less deformed and when 

 fertilized yielded no seed, hence the double character can only be introduced 

 from the staminate side, and this operation must be repeated in each genera- 

 tion. Doubleness was found to behave as the recessive and singleness as the 

 dominant character. 



White fl.owered varieties of Primula sinensis, F. Keeble and Miss C. 

 Pellew {Jour. Genetics, 1 {1910), No. 1, pp. 1-5.) — The authors state that 

 white flowered varieties of P. sinensis are of two liinds, one with red or red- 

 dish stems and the other with green stems. Colored stemmed whites, when 

 crossed with a variety with colored flowers, yield an Fi with white or tinged 

 flowers. Green stemmed whites, when similarly crossed, yield an Fi with 

 colored flowers. 



It is the purpose of this brief paper to record the existence of what appear 

 to be exceptions to the rule of dominant white among colored stemmed, white 

 varieties. 



Boot parasitism in Exocarpus, Margaret Benson {Ann. Bat. [London], 

 2-i {1910), No. 96, pp. 667-677, pi. 1, figs. 3).— A study is reported on species of 

 Exocarpus, a shrub found growing parasitically on a number of species of 

 woody plants. Comparisons are made with Thesium, a plant of similar habit. 



FIELD CROPS. 



The interpretation of experimental results, T. B. Wood and P. J. M. 

 Stratton {Jour. Agr. ScL, 3 {1910), No. J,, pp. 417-UO, figs. 10).— The authors 

 discuss the use of frequency curves and the calculation of probable error in the 

 interpretation of experimental data, illustrating the application of probable 

 error methods to questions of sampling for analysis and to field and feeding 

 experiments. 



The probable error of field experiments was studied by two independent 

 methods and estimated at about 5 per cent of the crop, regardless of the size 

 of plat employed, providing it is 1/80 acre or larger. By the use of large num- 

 bers of plats and systematic duplication, accurate results may be obtained with 

 plats as small as 1 square yard. 



The use of a single animal on a fattening ration gives a probable error of 

 about 14 per cent of the live-weight increase produced, and in an ordinary 

 experiment it is calculated that at least 29 animals must be used to obtain a 

 precision of 10 per cent. 



Tables show the number of animals or plats required to attain a given degree 

 of precision. 



