258 0. A. Derby— Stem Structure of Ttetea Singular is. 



distinguish them from the more internal members of the group 

 to which they belong, but on following them upwards it becomes 



apparent that those in the middle are mother strands destined 

 to give birth, by sprouting or subdivision, to future P and F 

 strands, while those at the sides, distinguished by the letter C, are 

 sterile. These last show evidence of having been formed, at least 



