10 Varietäten, Descendenz, Hybriden. — Physiologie. 



The author finds that xanthein, like anthocyanin, includes several 

 pigments which may be distinguished and classified by their reac- 

 tions towards acids, alkalies and basic lead acetate. The dissimila- 

 rity amung the xantheic pigments strengthens the view that the 

 anthocyanins, from which they are probably derived, are also 

 dissimilar. 



Albin ism. "It has been suggested that there are two forms of 

 anthocyanin .... one containing a yellow xantheic variety, the other 

 not. Whites occur in both series and it seems probable that the term 

 albinism should be used in a different sense when applied to each 

 of the two series. 



The extract from most white flowers . . . gives a canary yellow 

 with strong acids and alkalies . . . These whites may, without hesi- 

 tation, be declared to be recessive to the red-purple-blue types, and 

 they are albinos as regards anthocyanin. 



On the other hand, in the case of Antirrhinum, Asalea and 

 Phlox Drummondii, belonging to the series giving yellow sap-colour, 

 whites exist which do not give the same colour reaction. Moreover, 

 these whites are recessive to yellow in Antirrhinum and Phlox, and 

 are albinos as regards both anthocyanin and xanthein. It is the 

 ivory of this series which contains the glucoside-like body, and gives 

 the yellow colour reaction." 



The author points out that in Mirabilis Jalapa, which at first 

 sight appears to be an exception, both the red and the yellow pig- 

 ments are of an entirety different nature from those of Antirrhinum 

 and Phlox, and she suggests that the inheritance of Portulaca gran- 

 diflora will, if worked out, prove to be similar to that of Mirabilis. 



Plastid pigments. The plastid pigments, xanthin and Carotin 

 may both be present in the same plastid, the colour being an orange 

 yellow, or xanthin alone may be present, when the colour is yellow. 

 In cultivated varieties, xanthin appears to give rise to paler yellow 

 varities containing derivative pigments. The presence of Carotin is 

 dominant to its absence in Cheiranthus and Tropaeolum. 



Combinations of soluble and plastid pigments. An- 

 thoc5' , anin and plastid pigments are frequently found together in 

 plants. When the red sap occurs with plastids containing both 

 Carotin and xanthin, the resulting colour is some shade of brown 

 crimson or orange red; with plastids containing xanthin or its deri- 

 vatives only, the colour is maroon, purple or salmon-pink. The 

 series of colours formed by the combination of anthocyanin with 

 plastid pigments differs from the anthocyanin-xanthcic series in that 

 while in the former the type is crimson and the purple or magenta 

 is the derivative, in the latter the type is purple or magenta and 

 the derivative is crimson. This is exemplified in the genera Chei- 

 ranthus and Antirrhinum. 



The paper concludes with a Statement of the methods used in 

 the examination of the pigments, and numerous details are given as 

 regards the pigments present in genera of various natural Orders. 



R. P. Gregory. 



Gaulhofer, K., Ueber den Geotropismus der Aroideen- Luft- 

 wurzeln. (Sitzber. Wiener Ac. Wiss. CXVI. p. 1669 ff. 1907.) 



K. Linsbauer hatte im Jahre 1907 mitgeteilt (Flora, p. 267), dass 

 sowohl die Nähr- als auch die Haftwurzeln der Aroideen einen gut 

 ausgebildeten Statolithenapparat besitzen, obwohl doch nur die erste- 



