288 KARL lî. KHISTOFFERSON 



8. A correlation between tlie lengtti of the upper petals, the spin- 

 petal and the development of the labellum was noticed in Fz. On 

 account of the dominance in Fx and the correlations in F,, the presence 

 of an inhibiting factor common to the petals and the labellum was 

 assumed in the small flowering types. 



9. When a type with erect main axis and erect branches was 

 crossed with a type with prostrate axis and branches Fi became about 

 intermediate. F2 showed a continuous segregation as to these charac- 

 ters. Both these characters probably varied independently. An abso- 

 lute coupling was not at hand in any case. The différences in growth 

 form may be due to several factors, 



10. Types with different height gave an intermediate Fi when 

 crossed. The variation in F. was continuous between the limits of the 

 parents. 



11. The hybrids between V. Munbyana and different forms of V. 

 tricolor and V. arvensis had the appearance to be expected when a 

 violet of the large flowering type was crossed with the above discussed 

 species. 



12. A small Fsgeneration of a cross between V. arvensis and V. 

 Munbyana showed segregation in all characters investigated. 



13. The variation of the Swedish Mekminm violets V. tricolor and 

 V. arvensis is due to re-combination of Mendelian factors at least to 

 a very high degree. 



14. On account of the variation of the Fo-generation of crosses 

 between V. tricolor and V. arvensis and the variation in nature in these 

 species the author argues that they should be put together in one 

 single species, Viola tricolor L. 



LITERATURE CITED. 



1. Haur, E. 1906. Über die infektiöse Chlorose der Malvaceen. Sitz.-ber. preuss. 



Akad. Wissensch. 



2. — 1910. Untersuchungen über die Vererbung von Chromatophorenmerkmalon 



bei Melandriiim, Antirrhinum und Aqnilegia. Zeitschr. f. ind. Abst. u. 

 Vererb.-lehre. 



3. Candüllk, a. 1'. DE. 1824. Prodromus systematis naturaUs Regii vegetabilis. 



Pars I. 



4. Clausen, J. 1921. Studies on the Collective Species Viola tricolor L. Bot. 



Tidsskr. 37. Köbenhavn. 



5. CoRKKNS, C. 1909. Vererbungsversuche mit blass (gelb) grünen und bunt- 



blättrigen Sippen bei Mirabilis Jalapa, Urtica pilulifera und Lunaria annua. 

 Zeitschr. f. ind. Abst. u. Vererb.-lehre. 



