TRANSPIRATION BEHAVIOR OF RAIN-FOREST PLANTS. 105 



tory series with five species, and the figures are here repeated (table 

 44) for comparison with the rates for the moist chamber series (table 43) . 

 A comparison of the two columns of figures shows the first three 

 plants to stand in approximately the same relation to each other under 

 the two sets of conditions. The two ferns from the Windward Ravines, 

 however, exhibit lower rates of transpiration in comparison with Pepe- 

 romia basellcefoUa, as well as the other species, under moist-chamber 

 conditions. The significance of this fact is that the average play of 

 atmospheric conditions in the laboratory at Cinchona was less humid 

 than it is in the natural habitat of the two ferns, and they were con- 

 sequently exposed to a water loss greater than that which would take 

 place in the Windward Ravines. In other words, the two ferns were 

 subjected to a greater acceleration of transpiration by removal from 

 the rain-forest than were the other three species of the less humid 

 habitats. Such behavior on the part of Diplazium and Asplenium is 

 abundantly explained by the lightness of their epidermal water-con- 

 serving structures. In none of the experiments with these species were 

 they observed to wilt or show the least sign of loss of general turgidity, 

 although such appearances could be readily secured by exposing them 

 to half an hour of sunshine. The transpirational behavior of the ferns 

 in the shade of the laboratory is, therefore, normal in its character, 

 although the water losses are themselves higher in amount than in the 

 Windward Ravines (see p. 67 and p. 76). 



