226 BIOLOGY. 



clasp the stem inferiorly; or the petiole displays its 

 spathiform origin. In this case the leaf is not a part of 

 a hollow globe, but the entire globe, that has ruptured 

 in the transverse direction at the extremity of the pe- 

 tiole. Such is the case at least in the demispathiform 

 leaves of the Umbelliferous plants. 



1144. The primary position of the leaves like that of 

 the branches is thus verticillate, yet always, however, 

 under the idea of one being encased within the other. 

 The leaves are here only the ultimate branches. 



1145. If the leaves upon the ramules issue from each 

 other, then this happens in the same manner as with the 

 branches. 



1146. The verticillate position of the leaves is there- 

 fore the lowest, next succeeds the crucial, then the spiri- 

 form, and lastly the scattered. 



1147. The spathose leaves are only to be regarded 

 as a single bud, and therefore differ from the whorl, in so 

 far as we regard this as the development of several leaves, 

 that have not, however, been extruded from each other. 



1148. Divided leaves originate through a higher ope- 

 ration of light. In them the formation of ribs prepon- 

 derates, and therefore they rank higher than the un- 

 divided. 



1149. Prom this cause the pinnate leaves are the 

 highest. 



1150. From the same cause the radical must be 

 worse developed than the ramular leaves. They are 

 usually non-pinnated, undivided, because they have 

 more cellular substance in their composition than the 

 upper leaves. In the leaf-system, consequently, the 

 whole idea of the plant has been recontained ; on the 

 earth resides the chemical character, as is evidenced by 

 cellular, dense and misshapen leaves ; above in the air, 

 on the contrary, the leaves are more delicate and are 

 divided indicating an electric character. 



1151. The division and pinnation of leaves can only 

 progress according to the odd numbers, 3, 5, 7, because 

 the midrib determines the odd leaflet. 



