344 Origin of Each Species Considered Separately. 



considerably greater size during the summer and increase 

 the number of their leaves without, however, altering 

 their general appearance. A very typical leaf with its 

 venation will be found in Fig. 54 (See p. 295). 



If the rosettes develop stems in June and July they 

 flower that summer. Such plants are very uniform in 

 character, they are slender and yet firm, and branched 

 either very little or not at all. Hardly any differences 

 were discernible between 200 flowering plants growing 



Fig. 74, Oenothera ohlonga. A rosette with radical 

 leaves at the end of June. 



together. The tallest plant began to flower when it was 

 60 cm. high, and flowered till the end of September when 

 it had attained a height of one meter. It had a single 

 lateral branch only 10 cm. long and with only two flow- 

 ers on it ; all that there w^as in the way of lateral branches 

 besides this was a series of rosette-like offshoots from the 

 axils of the leaves along the middle region of the stem. 

 The result of this is the very characteristic ensemble 



