8 BOTANICAL GAZETTE [january 



Quadruple hybrids.— The discovery of twin and triple hybrids 

 naturally suggests the idea of the possibility of a hybrid quartette. 

 As a matter of fact the experiments did the same. In the case of 0. 



lata X O. biennis from Chicago a fourth type appeared in one speci- 

 men, and in that of O. lata X O. Hookeri in two specimens. These 

 three plants belonged evidently to the lata type, but combined with 

 this the smooth, broad, and bright-green leaves of the laeta, whereas 

 all the other latas of these crosses had gray and furrow-shaped leaves 

 like the velutina. The lata-laeta of the first cross was sufficiently 

 fertile, but of two of the Hookeri cross one had barren anthers and 

 the other only some spare pollen in comparison with the rich supply 

 of pollen in the other lata plants of this cross. In this respect, there- 

 fore, they also showed the character of the laeta type. 



It would seem probable that the lata-laeta should be produced in 

 the same number as the other lata, or lata-velutina as we could now 

 call it. But then the laeta itself often appears in too small numbers. 

 The cause of this phenomenon has still to be investigated. 



Summary 



i . Triple hybrids are produced in crosses of Oenothera scintillans 





American 



from O. Lamar ckiana 

 i Rydb., O. Hookeri ' 



from 



corresponding Lamarckiana crosses and bear the characters of O. laeta 

 and O. velutina combined with those of the other parent. 



4. The third type resembles the mother (O. lata or O. scintillans), 

 but in its special marks is also intermediate between its parents. 



5. The laeta and velutina are constant and uniform in their succeed- 

 ing generations, so far as experience goes. In this respect they follow 

 the rule for the twin hybrids of O. Lamarckiana. 



6. The lata, however, in the only case tried, repeated the splitting 

 after self-fertilization, producing, however, only lata and velutina. 



7- It seems probable that the whole progeny of the crosses named 

 should split up into two equal parts, laeta and velutina, and that each 

 of them should produce a certain percentage of lata. In this way 

 quadruple hybrids would arise. 



Botanic Garden 

 Amsterdam 



