I 9 i2] SHULL LYCHNIS AND PAP AVER 125 



drium album and my original white-flowered strain from Cold 

 Spring Harbor. Two of these families (10200 and 10202) were 

 the result of crossing two different German white-flowered females 

 with pollen from a single Cold Spring Harbor white-flowered male. 

 Both of these matings produced only white-flowered offspring, 

 totaling 182 individuals. The young seedlings were indistinguish- 

 able from Cold Spring Harbor seedlings of the same age, but later 

 they became darker green and were intermediate between the 

 parents. A third family (1068) was essentially reciprocal to the 

 two just described, being produced by crossing a female sib of 

 the male used in 10200 and 10202 with pollen from a German 

 white-flowered male. The 77 offspring were vegetatively indis- 

 tinguishable from the reciprocal families, but the flowers were all 

 reddish-purple. These different results in supposedly reciprocal 

 crosses probably indicate that there was an unsuspected hetero- 

 geneity in the German strain. That the difference was due to 

 heterogeneity in the Cold Spring Harbor parental family is rendered 

 improbable by the fact that a mating (1060) between the female 

 used as the mother of 1068 and the male used as the father of 

 10200 and 10202 resulted in a progeny of 73 white-flowered plants. 

 It is unfortunate that a similar check was not applied to the German 

 plants entering into these families, by also crossing them together. 

 The only cross (10203) made between two specimens of M . album 

 resulted in 84 offspring, all white-flowered. The mother of this 

 family was also the mother of 10202, but the father was not the 

 same as the father of 1068. 



Several crosses were also made between the purple-flowered 

 German Melandrium rubrum and my Cold Spring Harbor strains, 

 both white-flowered and purple-flowered. Families 1092 and 1093 

 were produced by crossing a single white-flowered female of the 

 Cold Spring Harbor strain with two males of M. rubrum, one 

 derived from seeds collected at Furtwangen in the Schwarzwald, 

 and the other from Oefmgen in Baden. A female sib of the last- 

 mentioned plant (i.e., from Baden) was crossed (10204) with 

 pollen from a white-flowered sib of the mother of families 1092 

 and 1093. It represented a cross, therefore, as nearly reciprocal 

 to 1093 as is possible in dioecious material. Two other families 



