OENOTHERA GRANDIFLORA AIT. 225 



1915, when I cultivated the second generation of the three types, 

 and could observe their distinguishing marks on large sets of plants. 

 In 1914 I counted one-half in the box, and the other at different 

 times on the bed; the sum of the two groups is given in the table. 



The culture of 1915 confirmed that of 1914, apart from its mutants. 

 I counted 11 ovata, 2 lutea, and 6 brunnea on the bed, besides 17-5 

 and 8 of the same types in the box. These latter have not flowered, 

 however, and for this reason are omitted in the table. 



0. grand if lor a lorea x 0. Lamarckiana nanella. 1 crossed a 

 mutant lorea in 1914 and a specimen of the second generation in 

 1915. The first cross gave, besides the flowering individuals of the 

 table, 39 ovata, 6 lutea, and 14 brunnea, which have not been planted 

 out for lack of space, but confirm the results of the other set. Almost 

 all of the plants of 1915 flowered in August. All these cultures have 

 been conducted after the same principles, and this makes the 

 description of further details quite superfluous. 



The current view concerning the mutations of Oenothera is that 

 they take place during synapsis and that the sexuall cells are in the 

 mutated condition before the moment of self-fertilization. If we 

 apply this to the mutability of 0. grandiflora, we may assume that 

 its sexual cells are divided into two main groups, about one-half 

 remaining typical, whereas the other half belong to the type ocfiracea. 

 Therefore the question arises, which of the triple hybrids just 

 described are produced by the typical gametes and which by the 

 mutated ones? In order to answer this question I made some crosses 

 in which I used 0. grandiflora mut. ochracea instead of the species 

 itself. The ochracea constitutes a constant and uniform race and 

 must obviously give the same hybrids as the mutated sexual cells 

 of the parent species. 



0. grandiflora ochracea x 0. Lamarckiana. — I made this cross in 

 1914 and had two sets of seedlings in 1915, one on the bed and the 

 other in the box. The first embraced 28 ovata and 2 lutea, the second 

 23 ovata with 3 lutea; together 56 plants. Those on the bed were 

 left to flower in August and the counting was then repeated. The 

 culture was one of the most beautiful in my garden and no doubt 

 was possible concerning the identity of the types. Notwithstanding 

 this, no brunnea and no contraria were observed. 



0. Lamarckiana x 0. grandiflora ochracea. — The result was 

 exactly the same as in the reciprocal cross, but the amount of lutea 

 was larger (16 specimens among 69). By the end of August almost 

 all the plants had flowered and were carefully compared with the 



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