324 Origin of Each Species Considered Separately, 



Although ^z^a^-plants can be recognized before they 

 flower it is difficult to give an accurate description of 

 their leaves because they exhibit a high degree of indi- 

 vidual variability — much greater in fact than do those 

 of the parent species. The greater breadth is the chief 

 difference; the length and general shape are about the 

 same. The leaves, moreover, of gigas are more crumpled 

 (compare page 310 and Fig. 62). But the breadth 

 which is usually a matter of 4-6 cm. sometimes sinks to 



Fig. 6s. Oenothera gigas. A young plant in June, a few 

 days before transplanting, (V2). 



2 cm. without however destroying the characteristic look 

 of the species. The leaves of the stem are usually set on 

 a shorter stalk and are more deeply toothed than in O. 

 Lamarckiana. The branches, of which a great many 

 develop, remain sessile in the axils of the leaves as short 

 densely foliate spikes which tend to make the foliage on 

 the stem much thicker, just as in O. ohlonga (Fig. 71). 

 The difference between the young rosettes in June 

 (when they are usually planted out) is very striking. 



