VEGETABLE CYTOLOGY 67 
of Mimosa , Oxalis, Drosera, Desmodium and Dionoea muscipula ex¬ 
hibit this phenomenon to a marked degree. A few instances only 
will be considered. When the tendrils of climbing plants come into 
contact with the uneven surface of solid bodies they are induced to 
coil. When the tentacles on a modified leaf of the Sundew (Dro¬ 
sera) are stimulated mechanically by an insect or artifically they are 
induced to curve over. If a good plant of the Venus Fly-trap (Dionoea) 
Fig.32. — Mimosa Spegazzini. After the application of a stimulus. Compare 
with Fig. 31. (After Steckbeck.) 
is selected, it will be seen to possess leaves, the terminal portions 
of which are modified as traps for catching insects (Fig. 30). Hairs 
will be seen projecting from the upper surface of each valve of the 
hinged blade-. If one of these hairs is touched with a pencil no re¬ 
action will be evident but if after a lapse of twenty seconds the hair 
is touched again, the 2 valves close. If the stamens of Berberis be 
touched near the base during their pollen shedding stage they will 
be observed to curve toward the stigma. 
