Varietäten, Descendenz, Hybriden. 85 



M X H --= 2 Grosses made. F^ all M. F^ plants from one cross not 

 examined further: the others carried to Fg which appeared bimodal, 

 H being recessive to M. This cross was carried to F^^ (1915) and a 

 group verj'- high segregated as a recessive from H. 



This is interpreted as indicating an additional factor introduced 

 by the M parent. 



L X H. There should be four types in Fj (A B, Ab, aB, ab). 



Results obtained were (1) L, M and H types produced (2) from 

 the four nodal characters of F2 there appeared to be four segre- 

 gates : i. e. there must be two types of M, AB and ab, dominant 

 and recessive M. Now dominant M X recessive M should produce 

 L and H in addition to M. The cross M X ^'^ from these F.2 plants 

 has been made unfortunately only once and yielded M only. 



It would be of interest to repeat this cross to see if the exi- 

 stence of these two types of M could be confirmed. 



There also occurs a definite ver}'^ low type corresponding to 

 the very high type. 



Types of nodal distribution were also noted, but it was not 

 found possible to explain these in terms of factors. 



As regard time of fiowering the L forms were „early", the M 

 forms „intermediate" and the H forms „late". 



Certain other „habit" characters were also considered but in 

 much less detail. 



The results of countings for several years is given very fully 

 in tables. W. Neilson Jones. 



Wheldale, M., The anthocyanin pigments of plants. (Cam- 

 bridge Univ. Press. 8°. 318 pp. 1916.) 



The present monograph is concerned almost exclusively with 

 the Problems that arise in connection with the soluble pigments of 

 plants, or anthoc^'-anins. The interest in these substances, chiefly 

 no doubt on account of their dying properties, is long Standing, 

 although the first experiraental investigation of them from a scien- 

 tific Standpoint does not date, probably, from earlier than the 17th 

 Century. The author opens with an introductory chapter which 

 serves the purpose of giving a general survey of the ground to be 

 covered in the volume. 



The following two chapters are concerned with the morpholo- 

 gical and histological distribution of anthocyanin and much useful 

 Information is coUected together as to the occurence of anthocya- 

 nins in different species and in different plant tissues under varying 

 conditions. The forms, solid, crystalline etc — in which the pigment 

 may occur are also discussed. 



Problems that are more purely chemical, such as the chemical 

 properties, Isolation and Constitution, together with the probable 

 reactions involved during the formation of anthocyanins, are treated 

 in following chapters with as much fullness as a botanist is likely 

 to desire. Other chapters deal with the physiological conditions and 

 factors infiuencing the formation of anthocyanins and the possible 

 significance of these pigments to the plants producing them. 



The second part of the volume is devoted to the consideration 

 of Problems of inheritance involving anthocyanins. 



It is here that the author considers the chief interest in the 

 anthocyanins to lay; since we have now satisfactory methods for 

 the Isolation, analysis and deterraination of the constitutional for- 



