356 Origin of Each Species Considered Separately. 



For example in 1895 I found 5 leptocarpa amongst 

 44 tricotylous nihrinervis (p. 273) and in 1897 I found 

 one amongst 20. In 1900 I had planted out 24 apparent 

 Lamarckiana plants which had sprung from a cross which 

 I had made in 1899 between O. nihrinervis and O. nanella. 

 When they came to flower, however, it turned out that 

 only half of them were really Lamarckiana and that the 

 rest were leptocarpa. In the same year two leptocarpa 

 appeared among the 90 offspring of a cross between 0. 

 nihrinervis and 0. Lamarckiana. 



The most characteristic features of O. leptocarpa 

 are its late flowering and its long slender fruits. The 

 late flowering is not the result of arrested growth for 

 the plants are just as strong and as tall as others when 

 these are about to flower; but it is due to the fact that 

 after they have reached this stage they continue to grow 

 vegetatively for some weeks to come. The first flower- 

 bearing node is therefore considerably higher in lepto- 

 carpa than in other forms and the spike of flowers 

 standing well above those of the other plants on the 

 bed enables us to detect the species immediately. The stem 

 is, moreover, rather flaccid so that the flowering spike 

 hangs over to one side. The flowers and buds do not 

 differ in any essential feature from those of 0. La- 

 marckiana; the buds are, just before they open, a slightly 

 brighter green with less yellow in them. The fruits and 

 bracts on the other hand are quite different. The bracts 

 are broader at their base, more triangular and more 

 flattened, whilst those of 0. Lamarckiana are often more 

 or less bent and wavy along the midrib. They are pressed 

 much more closely against the stem which they almost 

 completely enclose in a mantle, as it were: instead of 

 hanging down they stand up fairly straight. Finally 



