Characters of the New Species. 451 



3. Branches weak, and so bent down- 

 wards, top of plant also weak . . .12. O. lata. 

 B. Almost unbranched, branches in the 

 form of rosettes, stem very thin (Fig. 



50, 71). . . U. O.oblonga. 



III. Dwarf, often flowering when only 10-20 



cm. high (Fig. 45, 77) 14. O.nanella. 



In Oenothera Lamarckiana every part of the plant has 

 a characteristic type of leaf from the seedling to the 

 top of the inflorescence. The same is true of the new 

 species which have arisen from it. The radical leaves 

 of the full grown rosettes merge by imperceptible de- 

 grees into the lower leaves of the stalk. As we ascend 

 the stem, the leaves become gradually shorter and set 

 on smaller stalks until we reach the inflorescence, at the 

 bottom of which, or slightly later, they become almost 

 sessile. In the young inflorescence they extend beyond 

 the flowers, but, later on, become relatively small com- 

 pared with them. The greatest breadth of the leaf, 

 which at the bottom of the plant is about its middle, 

 gradually shifts, as we ascend, to its base. In describing 

 the leaves of the different new species we must therefore 

 compare only such as are borne on the same part of the 

 stem. 



ANALYTICAL TABLE OP THE LEAVES. 

 I. Of normal breadth. 



A. Of normal length and form. 



1. Pointed. 



a) (Figs. 62, 89) \. O. Lamarckiajia. 



b) 2. O. leptocarpa. 



2. Rounded 3. O. brevisfylis. 



B. Roundish 4. (7. semilata. 



C. Short, sessile or with a short stalk; broad at 



the base; often auriculate or heart shaped 5. O. nanella. 

 II. Broader. 



A. Of the same form, but very variable, 

 teeth large, numerous, especially at the 



