588 HorNnE: ANOMALOUS STRUCTURE ON LEAF OF BEAN 
the lignified elements disappear and the central strand becomes 
much narrower. FIGURE 3 shows somewhat diagrammatically the 
relation of the different parts. FiGuRE 4 shows a section at about 
the center of the group of vessels, and FIGURE 5 shows the struc- 
ture of the tip. 
The first structure was a true root formed in a somewhat un- 
usual position, The second is probably best regarded as an an- 
omalous appendicular structure. The stimulus of high tempera- 
ture and humidity probably favored the growth of these unusual 
structures. 
