352 Literatur 
Vaır, A. M., Onagra grandiflora Ait, a species to be included in the North American 
flora. 
Torreya, Vol. V S. 9. 1905. 
de Vrıes, Hv6o, On atavistic variation in Oenothera ceruciata. 
Bull. Torrey Bot. Club, 1903 p. 75. 
— Teunisbloemen in Amerika. 
Album der Natuur. 1905. p. 193—209. 
— Über die Dauer der Mutationsperiode bei Oenothera Lamarckiana. 
Ber. d. d. bot. Gesellsch. Vol. 23 p. 382. 1905. 
— On Twin hybrids. 
Bot. Gaz. Vol. 44. p. 401—407. 1907. 
— Über die Zwillingsbastarde von Oenothera nanella, 
Ber. d. d. bot. Ges. Bd. XXVlIa p. 667—676, 1908. 
— Bastarde von Oenothera gigas. 
Ber. d. d. bot. Ges. 1908. Bd. XXVlIa. S. 754—762. 
— On triple hybrids. 
Bot. Gaz. Vol. 47. p.1—8, 1909. 
— Über doppeltreziproke Bastarde von Oenothera biennis L. und O. muricata L. 
Biol. Centralbl. Bd. 31 p. 97—104. 1911. 
— Oenothera nanella, healthy and diseased. 
Science NS. Vol. 35 Nr. 906 8. 753. 1912. 
ZEYLSTRA, H. H., Oenothera nanella de Vries, eine krankhafte Pflanzenart. 
Biol. Centralbl. Bd. 41 p. 129—138. 1911. 
— Over de oorzaak der dimorphie by Oenothera nanella. 
Kon. Akad. v. Wet. Amsterdam 1910 S. 732—737. 
— On the cause of dimorphism in Oenothera nanella. 
Proceed Roy. Ac. of Sc. Amsterdam 1919. 
