60 



LEAVES. 



[SECTION 7. 



158. Perfoliate Leaves. In these the stem that bears them seems to 

 run through the blade of the leaf, more or less above its base. A. common 



Bellwort (Uvulai-ia perfoliata, Fig. 



163) is a familiar illustration. Tlie 



lower and earlier leaves show it 



distinctly. Later, the plant is apt 



to produce some leaves merely 



clasping the stem by the sessile 



and heart-shaped base, and the 



latest may be merely sessile. So 



the series explains the peculiarity : 2g^ 



in the formation of the leaf the 



bases, meeting around the stem, grow together there. 



159. Connate-perfoliate. Such are the upper leaves of true Honey- 

 suckles. Here (Fig. 163) of the opposite and sessile leaves, some pairs, 

 especially the uppermost, in the course of tlieir formation unite around the 

 stem, which thus seems to run through the disk formed by their union. 



160. Equitant Leaves. While ordiuary leaves spread horizontally, and 

 present one face to the sky and the other to tlie earth, there are some that 

 present their tip to the sky, and their faces right and left to the horizon. 

 Among these are the equitant leaves of the Iris or Flower-de-Luce. In- 

 spection shows that each leaf was formed as i( folded together lengthwise. 



Fig. 162. A summer branch of Uvularia perfoliata; lower leaves perfoliate, upper 

 cordate-clasping, uppermost simply sessile. 



FiQ. 163. Branch of a Honeysuckle, with connate-perfoliate leaves. 



Fig. 164. Rootstock and equitant leaves of Iris. 165. A section across the 

 cluster of leaves at the bottom, showing the equitation. 



