STRATIFICATION 



165 



TABLE XXXVI 



EVAPORATION FROM POROUS CUP EVAPORIMETERS IN DIFFERENT STRATA OF A 

 SUMMER DRY MARSH, CAMBRIDGESHIRE, ENGLAND, DURING THREE 

 PERIODS BETWEEN JULY 9 AND SEPTEMBER 8, 1907 

 (Yapp, 129, p. 299) 



Table XXXVI shows marked differences in the rate of evaporation 

 and considerable differences in temperature at the different levels, both 

 due largely to vegetation. Differences in light are also to be expected. 

 Sherff (136, p. 420) has found conditions similar to the above by a two 

 months' study of evaporation on Skokie Marsh near Chicago. The 

 evaporation there was three times as great at a height of 1.95 m. as at 

 the surface of the soil in among the plants of Phragmites. Mr. Harvey 

 has secured similar (unpublished) results on the prairie at Chicago 

 Lawn, Chicago, also Mr. Fuller, in the beech woods. 



Division into strata: Plant and animal habitats are commonly 

 divided into strata as shown below. 



Plant (12) after Warming 

 i. No such stratum recognized. 



2. Ground stratum made up of algae, 

 mosses, immediately above the sur- 

 face of the ground. 



3. Field stratum; grasses and herbs. 



4. Shrub stratum; formed of shrubs 

 taller than the herbaceous vege- 

 tation. 



5. Tree stratum. 



Animal 



1. Sub-aqueous stratum made up of 

 animals requiring water during 

 their active reproductive stages. 



10. Subterranean stratum made up 

 of animals or stages in the life 

 histories of animals which inhabit 

 the ground, especially during the 

 breeding season. 



2. Ground stratum made up of ani- 

 mals or early stages in the life his- 

 tories of animals, as i. 



3. Field stratum; the inhabitants of 

 the herbaceous vegetation on land. 



4. Shrub stratum; inhabitants of 

 shrubs. 



5. Tree stratum; inhabitants of trees. 



