REACTIONS OF STAMENS TO SHOCK 



Strike the terminal leaflets of a normal specimen of Biophytum 

 so lightly that no reaction ensues and repeat at intervals to de- 

 termine the memory, or time during which the stimulus-effects are 

 retained and cumulated, finally producing full excitation. 



26. Reactions of Stamens 

 of Opuntia to Shock. The 

 flower of Opuntia contains 

 a single central style sur- 

 rounded by a number of 

 shorter stamens. Bees or 

 other insects entering the 

 flower in quest of honey 

 pass down the style, touch- 

 ing the filaments of the Sta- FIG. 6. Sections of two flowers of Opuntia. 

 mens. As a result of Such c > with stamens in normal position, d, with sta- 



stimulation the stamens mens bending toward the style in res P nse to 



shock of rough objector insect. After Tourney. 



curve inwardly toward the 



style, forming an arched cage with the style in the center, in 

 which the bee is imprisoned. In brushing aside the 

 anthers to escape the bee carries away some of the 

 pollen, which may be left in another flower, effect- 

 ing cross pollination. The curvature of the 

 filaments is so rigid that the bee may be held for 

 several minutes, and its struggles act as repeated 

 stimuli, causing tetanus of the filaments. After a 

 time, however, the organs become accustomed to 

 FIG. 7. Pis- the repetition of the stimuli, the tetanus is relaxed 



til of Mimulm. anc j fa e filaments straighten out to their original po- 



b, expanded po- .,. .. . - Tr ., . 



sition a after Sltlon > allowing the insect to escape. If it is not 

 irritation of the possible to observe this action, imitate the behavior 

 stigmatic sur- o f the bee with a small wire or wooden splinter. 1 



Similarly sensitive stamens may be found in 

 Mammillaria, Echinocactus, Echinocereus and other 

 reactions may be seen in Berberis, and in some of the Cichcria- 



1 Tourney, J. W. Sensitive stamens in the genus Opuntia. Asa Gr<*y Bull. 7 : 

 35- 1899. 



faces. After 

 Belzung. 



