Other Characters in Oenothera Lamarckiana. 485 



Pitcher formation came under my notice ten times 

 altogether, in 1887 and 1892 in the field at Hilversiim, 

 in 1889 and later in my own cultures. The first two 

 pitchers occurred on fasciated stems (Fig. 109), the 

 third on an 0. lata, two on O. laevifolia (1891, 1895), 

 two on 0. alhida (1898), two on O. Lamarckiana 

 (1891, 1895), and one on O. nanella (1897). In these 

 cases the pitcher usually took the place of a leaf about 

 the middle of the stem when the plant was in flower, 

 that is to say below the inflorescence; but the point of 

 attachment to the stem always seemed to have been dis- 

 placed upward. The pitchers were small, usually from 

 1 to 3 centimeters long; their dorsal side being usually 

 three times as long as the ventral. They were set on long 

 thin stalks about 3 centimeters in length. 



Pitcher formation was also observed in the first leaves 

 of young seedlings. Ascidia also occurred in 0. biennis, 

 in 0. Lamarckiana X biennis (1896) and O. Lamarck- 

 iana X suaveolens (1897). In 1897 I found in a fairly 

 small culture of 0. hirtella five young plants with a 

 pitcher on the top of the stem which interfered with the 

 flowering of the main shoot. 



This repeated, though rare, appearance of the phe- 

 nomenon, scattered as it is pretty evenly over the various 

 families, points to the conclusion that it is inherited in 

 a latent state. ^ 



Concrescence of two successive leaves on the stem 

 also occurred, though rarely : I first saw it in 1887. Syn- 

 anthy in the axils of leaves which had become concrescent 

 or at any rate grown too close together, sometimes oc- 



^ Over de erfelykheid van Syntisen, Kruidkundig Jaarboek Do- 

 donaea; T. VII, p. 129; for Oenothera see p. 165. 



