24 



BURSA BURSA-PASTORIS AND BURSA HEEGERI : 



The second of two original plants of B. bp. rJiornboidea (040.8) produced 

 330 offspring-, all but 5 of which possessed characters recog-nized as prop- 

 erly belonging: to the parental type, namely, distinct obtuse lateral lobes, 

 usually with an incision on the distal marg-in and sometimes with a similar 

 incision on the proximal marg-in (fig. 16). The 5 individuals which were 

 aberrant from the type of the other 325 had the essential characters of B. 

 bp. heteris. As will be seen later, heteris is dominant over rhomboidea, and 

 the simplest explanation of the presence of these 5 specimens of heteris in 



FiG. ]5. — Bursa bitrsa-pastoris 7-homboidea. Grown in nearly saturated air 

 and moderate illumination. Leaves very thin and translucent. 



a family of rJiomboidea is the supposition that they represent chance crosses 

 between these two biotypes. 



Another culture which was not at first thought to be referable to B. bp. 

 rhomboidea was raised from seeds of a plant (050.82) growing in a door- 

 yard near Cold Spring Harbor, Long Island. The parent had rather small 

 leaves with crowded lobes and coriaceous texture. The lobes had a strongly 

 marked distal incision and rarely a slight proximal incision (fig. 17). This 

 plant was removed to the greenhouse April 18, 1906, and the flowers were 



