46 MINUTE MARVELS OF NATURE 



wider cells than the compacter layer formed later 

 in the year. 



Fig. 29 shows a section of a stem with longi- 



Fig. 29. Clematis has longitudinal furrows on its stem which show 

 in this section 



tudinal furrows, one of the numerous variations 

 which the stems of plants assume. Some are 

 flattened, others triangular ; and a square stem 



