420 Varietäten etc. — Physiologie. 



of greater Variation than the specialized t5'pe. The garden cultures 

 were confined to several species of native cacti, which were given 

 a good supply of water for 24 months and were grown in deep 

 soil. He finds that an abundant supply of water operates to lessen 

 the differentiation of the roots, and, in addition. to bring about a 

 somewhat deeper placing of the root System. Harshberger. 



Cavara, F., Chimere settorali negli agrumi. (Bull. Soc. bot. 

 ital. p. 11-14. 1912.) 



Description d'un cas de Variation par bourgeons chez Citrus 

 Bigaradia var. canaliciilata Risso; il produit sur quelques unes de 

 ses branches des fruits presentent les caracteres de l'espece C. Bi- 

 garadia. Apres avoir elimine l'hypothese d'une greffe directe, d'hy- 

 bridation ou de mutation gemmaire, l'auteur pense qu'on pourrait 

 probablement rapprocher ce cas des phenomenes de chimeres secto- 

 riales signalees par Winkler. C. Bonaventura (Firenze). 



Ponzo, A., Sulla variazione numerica nei tiori di Ranuncu- 

 lus Ficaria. L. (Bull. Soc. Bot. ital. p. 48—54. 1912.) 



Recherches biometriques sur le nombre des sepales et des pe- 

 tales des fleurs de Ranunciilus Ficaria, accomplies sur des fleurs 

 recueillies ä Trapani (Sicile), et conduisant ä des chiffres diffe- 

 rentes de ceux determines par Preda sur les fleurs de la meme 

 plante recueillies ä Spezia: sur 900 fleurs l'auteur a observe une 

 Proportion de 97, P/o de fleurs ä 3 sepales (Preda 62,5% sur 700 

 fleurs); le nombre des petales le plus frequent est 11, la moyenne 

 correspondante 11,6 (Preda 9;. 



C. Bonaventura (Firenze). 



Vilmorin, P. de, Sur une Race de Ble nain infixable. (Journ. 

 of Genetics. III. 1. p. 67—76. 1 pl. 8 flg. 1913.) 



Amongst normal plants of two varieties oi Triticinn sativum ("Be- 

 seler's Brown Club head" and "Shirno") dwarf plants were discovered. 

 On subsequent breeding it was found that: 



1) the dwart race never bred true but always threw a Propor- 

 tion (from I to I) of normal tall plants; 



2) the tall plants of the same origin bred true. 



The Author brings forward two possible hypotheses to account 

 for this behaviour a) normal segregation occurs in the simple Men- 

 delian ratio 1:2:1 but the dwarf homozygotes are not viable h) 

 repulsion exists between gametes carrying "dwarfness". The latter 

 is regarded as the more probable explanation. The Author holds 

 that the factors for "Tallness" and "Dwarfness" in these two races 

 are different in nature from the corresponding factors in other 

 races of wheat in which Tallness is dominant. 



W. Neelson Jones (London). 



Ciamician, G e C. Ravenna. Sul contegno di alcune 

 sostanze organiche neivegetali. 2a Memoria. (Mem. 

 R. Acc. Scienze dellTstit. Bologna, ser. 6a. VI. 1908- 1909.) 



Recherches sur la maniere dont se comportent dans les plantes 



