Summation of Dissimilar Stimuli Applied to Leaflets of Sensitive Brier (schrankia)

1. The pinnae of sensitive brier or Schrankia are favorable for demonstrating summation of dissimilar stimuli. 2. The demonstration was made as follows: A time of day was chosen when the closure of a single proximal leaflet did not provoke closure of the next distal leaflet. An irritating gas was applied to the pinna. A few seconds later, a single leaflet was touched; it closed, induced closure of the next distal leaflet, and inaugurated a wave of closure which proceeded until all leaflets on the same side of the mid-rib were closed.