272 Shull. 



Tliere appears to be no correlation between the average length of 

 "bristles" in the narrow-leafed group of an}' family and the broad-leafed 

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

 lation being — 0'024 4:0"117. This indicates that there was probably 

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

 mentary ovary in these families. 



II. Genetic studies with Lychnis dioiea angiistifolia. 



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 tliis 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 (Ped. No. 10244)i) consisted of 

 72 males and 8 females. In the F2 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 F2 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. la my cultures of the F2 gi'own 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 i)lants 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 Bach'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. 



