AGRICULTURAL BOTANY. 433 



Mendelian recombinations but possess many characters which have been 

 modified. 



The author considers that mutation as a process is not to be confounded with 

 the mere recombinations of unit characters, and that various types of heredi- 

 tary behavior exist, only occasional characters showing the Mendelian type 

 of segregation. 



Note on g-ametic reduplication in Pisum, Caroline Pei.lew {Jour. Genetics, 

 S {1913), Xo. 2, pp. 105, 106). — An account is given of crosses made between a 

 tendrilled variety of peas having wrinkled seed and a round-seeded acacia form, 

 the object of the cross being to see whether among the gametes of Fi repulsion 

 between the factors, tendrils, and round seed would occur. The F2 seeds were 

 sorted into round and wrinkled, and the result showed that repulsion occurred. 

 It is considered to be presumably only partial, but the proof is thought to be 

 beyond the scope of practical experiment on account of the large number of 

 plants involved. 



In view of the possibility that factors other than roundness might couple 

 with the factor for tendril, crosses were made in which various factors were 

 introduced with the tendril and acacia characters, but no signs of coupling or 

 repulsion were observed in F2 from such crosses. 



A quantitative study of the factors influencing the weight of the bean 

 seed. — I, Intra-ovarial correlations, J. A. Harris {Bot. Centhl., Beihefte, SI 

 {1913), 1. AU., No. 1, pp. 1-12, pis. 4). — This paper, the first of a series dealing 

 with the physiology of seed production, gives data regarding the characteristics 

 of the pod and the weight of the bean seed. 



It is stated that the correlation between such weight and the number of 

 ovules per pod is so low as to be practically negligible. That between number 

 of seeds matured per pod and seed weight is low but decided, being always 

 negative. The chances for an ovule to develop into a seed are generally 

 greater toward the stigmatic end. The weight of the seed shows the same 

 general kind of correlation, but this finally becomes less marked as the distal 

 end is approached. 



The cultural bud mutations of tuberous Solanums, E. Heckel {Rev. Sci. 

 [Poris], 51 {1913), II, No. 19, pp. 577-582).— The author describes the work 

 which has been done in inducing what he calls bud mutations in tuberous 

 Solanums, and interprets the results obtained in relation to the criticism that 

 such transformations are not true mutations. 



On the presence of connecting threads in graft hybrids, Mabgabet Hume 

 {New PhytoL, 12 {1913), No. 6, pp. 216-221, fig. 1).—A study was made of the 

 graft hybrids Cytisus adaini, Solarium tuhingense, and S. kcelreuterianum with 

 a view to determining the presence of connecting threads between the different 

 elements. 



From the experiments the author draws the conclusion that if Baur's 

 hypothesis that graft hybrids really are periclinal chimeras is true, and there 

 is every reason to believe that it is, there is no doubt that genetically unrelated 

 tissues can be joined by connecting threads. The threads arise secondarily, 

 since it Is supposed that the naked cytoplasm of the two components does not 

 come into contact. 



Anatomy as a means of diag-nosis of spontaneous plant hybrids, R. Holden 

 {Science, n. ser., 38 {1913), No. 991, pp. 932, 553).— From a study of forms of 

 Betula pumila from the Arnold Arboretum and of a variety of Equisetum. the 

 author is led to the conclusion that six)ntaneous hybrids are of common occur- 

 rence and that they can be clearly diagnosed as hybrids by an investigation of 

 their vegetative and reproductive internal anatomy. It is believed that an in- 



