570 



THE AMEBIC AN NATURALIST [Vol. XLVII 



the characters of Lamarckiana. It is of course in no way 

 essential to the hypothesis of the hybrid origin of La- 

 marckiana that the plant should have arisen as the 

 product of a simple cross. With Lamarck's plant elimi- 

 nated from the problem of the origin of De Vries's ma- 

 terial, the importance of grandiflora, on historical 

 grounds, is materially lessened and we may consider 

 other large-flowered types of more recent introduction 

 into Europe as possible parents in a cross. 



The resemblance of my various hybrids to Lamarckiana 

 and the parallelism of their behavior in the F 2 and F 3 to 

 that of Lamarckiana give in themselves sufficient reasons, 

 in my opinion, to justify the belief in its hybrid character 

 and to point to the probability that this plant arose as a 

 cross between distinct forms of (Enothera. Lamarckiana 

 thus would not be representative of a wild species of 

 essentially stable germinal constitution and its "muta- 

 tions" are most simply interpreted as the behavior of a 

 hybrid. 



University of Pennsylvania, 

 April, 1913 



utki; \t n;K < m:i> 



, B. M., 1910. Notes on the Behavior of Certain Hybrids of CEnotherc 

 i the First Generation. Ameb. Nat., Vol. XLIV, p. 108, 1910. 



B. M., 1911. Some Hybrids of (Enothera biennis and 0. grandiflon 

 lat resemble 0. LamarcTciana. Amer. Nat., Vol. XLV, p. 193, 1911 

 , B. M., 1912a. Further Hybrids of (Enothera biennis and 0. grandi 



nge) a form o 



v\s, B. XL, 1913. Mutations in (Enothera biennis L.? 

 XLVII, p. 116, 1913. 



Vries, Hugo, 1901. Die Mutationstheorie. Leipzig, 1 

 it, E. M., 1912. The Mendelian Notation as a Descrij 

 ical Facts. Amer. Nat., Vol. XLVI, p. 633, 1912. 



