58 THE AMERICAN BOTANISi 



only when it is more than a few inches in diameter, while in 

 tropical forests some can embrace enormoub tree trunks. 



The runners of creeping plants have a very complex 

 movement. It is obvious that this movement aids them in 

 finding a passage between surrounding plants and other ob- 

 structions. If they did not circumnutate, their tips would 

 come in contact with obstructions and double up, thus hinder- 

 ing the spreading of the plant from the parent stock. Their 

 chief motion is vertical and due to the weight of the end of 

 the stolon, the ellipses formed have long vertical and very 

 short horizontal axes. 



{To he continued) 



A NEW FORM OF KEY 



AT O matter how carefully the technical keys are construct- 

 "*• ^ ed by the skilled botanist, the novice always has more or 

 less difficulty with them. It is not easy to follow directions in 

 all cases and a single slip, of course, lands him in a group that 

 may be quite remote from the one his plant is in. The Key 

 on the opposite page is not open to this objection for all the 

 searcher has to do is to follow up the lines from Liliales on the 

 bottom line until he reaches the genus he is in search of. being 

 careful to take the correct line at each fork of the road. 



The Key is not designed to show relationships though it 

 naturally throws similar plants together and therefore gives 

 the beginner a somewhat comprehensive survey of the group 

 to which his plant belongs. The genera keyed out here arc 

 those in the two most important families of the Liliales. If 

 it proves serviceable to students, keys of the other groups 

 may be printed in later issues. 



