262 Descendenz und Hybriden. 



BlDGOOD, J., Albin ism. (Journ. Royal Hort. Soc. London. 

 May 1904.) 



The author points out that albinism is an extremely common 

 occurrence in plants, and that albinos breed true if self-polli- 

 nated or if pollinated by their own kind, and no evidence is 

 known oi seif pollinated albinos ever producing coloured off- 

 spring. If however they are crossed with other species con- 

 taining similar pigmenti and presumably if crossed with their 

 own coloured type, the typical colours reappear. Cyprepedium 

 insigne Sanderae has been self-pollinated and the offspring 

 have proved true, but when crossed with another species the 

 pigments have reproduced in greater or Iess degree the colour 

 arrangement of typical C. insigne. In the shirley-poppy a case 

 of „local albinism" is found, the colour having completely dis- 

 appeared from a portion of the flower. The history of this 

 plant is interesting. 



The origin of the Shirley Poppy was the seed of a single 

 flower of P. Rhoeas found by Wilks in his garden in 1880, 

 the petals having a narrow white edge. Its seeds were sown, 

 and the next year four or five plants had petals with white 

 borders. As cultivation was continued for several years, the 

 petals gradually showed a more extensive infusion of white, 

 until they acquired a pale pink colour, and one plant had 

 flowers absolutely pure white with the exception of the black 

 blotch at the base of the petals which had hitherto persisted 

 in all the flowers. Suddenly however it disappeared from one 

 plant, Ieaving a white patch in its place. By selection of such 

 plants the black colour was entirely eliminated and for several 

 years Wilks has not obtained one black-patched plant. Seeds 

 supplied by the trade however throw black-patched plants fairly 

 frequently. 



It is to be observed that the race has been obtained by 

 simple selection, and is quite pure, and so long as they polli- 

 nate one another they breed true. 



Black Colour in plants is stated to be generally due to red 

 pigment overlying cells containing abundant Chlorophyll, as on 

 Ieaves of Arum maculatum and the spotted form of Ranun- 

 culus Ficaria. Chemical examination shows that the black 

 pigment of the base of the petal and that of the rest of the 

 petal are different, and to some extent this may account for 

 the independent colour Variation of the two regions. 



E. Drabble (London). 



DARBISHIRE, A. D., On the Results of Crossingjapanese 

 Waltzing Mice with Albino Mice. (Biometrica. Vol. III. 

 Pt. I. January 1904.) 



The forms used were I) the Japanese Waltzing mouse, 



which is characterized by its habit of spinning round; the mice 



used had pink eyes and patches of fawn-colour in the coat. 



The ränge of Variation in colour was practically zero. All the 



