FOLIAGE LEAVES. 



405 



775. Rosette pattern. The rosette pattern is presented by 

 many plants with "radial" leaves, or leaves which arise in a 

 cluster near the surface 



of the ground, and are 



thus more or less crowded 



in their arrangement on 



the stem. The pretty 



gloxinia often presents 



fine examples of a loose 



rosette. In the rosette 



pattern the petioles of 



the lower leaves are 



longer than the upper 



ones, and the blade is 



thus carried out beyond 



the inner 'eaves. The 



leaves being so crowded 



in their attachment to 



the stem lie very nearly Fig. 44 2. 



in the same plane. 



776. Vines and climbers. Some of the most extensive mosaic 

 patterns are shown in creeping and climbing vines. A very 

 common example is that of the ivies trained on the walls of build- 

 ings, covering in some instances many square yards of surface. 

 Where the vines trail over the ground or clamber over other 

 vegetation, it is interesting to observe the various patterns, and 

 the distortion of petioles brought about by turning of the leaves. 

 Of examples found in greenhouses, the Pellonia is excellent, and 

 the trailing ribbon-grass often forms loose mosaics. 



777. Branch patterns. These patterns are very common. 

 They are often formed in the woods on the ends of branches by 

 the leaves adjusting themselves so as to largely avoid shading 

 each other. Figure 443 illustrates one of them from a maple 

 branch. It is interesting to note the way in which the leaves 

 fit themselves in the pattern, how in some the petioles have 

 elongated, while others have remained short. Of course, it 



