272 Shull. 



There appears to be no correlation between the average length of 

 "bristles" in the narrow-leafed group of any family and the broad-leafed 

 group of the same family, as shown by Fig. 3, the coefficient of corre- 

 lation being 0* 024 + 0' 117. This indicates that there was probably 

 no other genetic factor affecting differentially the length of the rudi- 

 mentary ovary in these families. 



IT. Genetic studies with Lychnis dioica angvstifolia. 



As already indicated, the original narrow-leafed plant appeared 

 singly among more than 100 broad-leafed offspring of a controlled cross 

 between two specimens of Melandrium album secured from nature at 

 Sadowa near Berlin. This plant was a male, and the Fi produced by 

 crossing it with broad-leafed females, consisted entirely of broad-leafed 

 males and broad-leafed females. Dr. BAUE did not make an exact deter- 

 mination of the sex-ratio in this family, but noted that there was a marked 

 excess of males, as he had found generally in his cultures of Melandrium 

 album (BAUE 1912). In my garden the Fi (Fed. No. 10244) 1 ) consisted of 

 72 males and 8 females. In the F 2 grown in 1912, BAUE found among 

 151 plants, 112 broad-leafed and 39 narrow-leafed, a ratio of 2*87 : 1, 

 a sufficiently close agreement with the monohybrid ratio. His total 

 cultures of the F 2 contained about 300 plants, a part of which were 

 not exactly counted. Of these, 52 narrow-leafed individuals and 3 broad- 

 leafed were set into the garden to complete their development. All of 

 the former were males, and by a peculiar coincidence, since males were 

 normally present in excessive proportion in this strain, all of the three 

 broad -leafed plants were females. In my cultures of the F 2 grown at 

 the same time, no selection had been made. Only 50 seeds were sown, 

 and every seed germinated, producing 50 plants, 44 of which were 

 broad-leafed and 6 narrow-leafed. One of the broad-leafed plants failed 

 to bloom, and the rest consisted of 32 females and 11 males. All 

 of the narrow-leafed plants were males. BAUE then made a second 

 sowing from the same lot of seeds and secured 55 broad -leafed and 

 21 narrow -leafed plants. Owing to the lateness of the season when 

 these were sown, none of the narrow-leafed plants bloomed, but 20 broad- 



*) By an oversight in a recent paper (Ber. d. Deutsch. bot. Gesell. 31: General- 

 versammlungs-Heft, pp. 40 80, 1914) I have represented this family as the offspring 

 of BAUR'S white-margined plant, M. 1. The mother of my 10244 was BAUR'S M. 2, 

 which was itself produced from a seed of the white-margined part of M. 1. The father 

 of 10244, as there correctly indicated, was the narrow-leafed mutant M. 3. 



