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) 
_ TEMPERATURE 
ATIO OF —_ = 
Bia BOE EVABORA i “ 
TION | ean ean 
Max. | Min. | Mean 
5 ft.6in.to4ft.6in..| 100.00 | 22.1 6.6 | 16.5 | Well above vegetation 
DUE E ay 2 NIA acid ont reese Bats 23.0 | .... | .... | A little above the mid-height 
Gish ae eater tet es aA eee GAG I) addeow | Fron |e 
SOLD eres ieceersiseate| rate diate TORT |e 2a eS 
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has secured similar (unpublished) results on the prairie at Chicago 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 Animal 
1. No such stratum recognized. 1. Sub-aqueous stratum made up of 
: animals requiring water during 
their active reproductive stages. 
1a. 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 algae, 2. Ground stratum made up of ani- 
mosses, immediately above the sur- mals or early stages in the life his- 
face of the ground. - tories of animals, as 1. 
. Field stratum; grasses and herbs. 3. Field stratum; the inhabitants of 
the herbaceous vegetation on land. 
4. Shrub stratum; formed of shrubs 4. Shrub stratum; inhabitants of 
taller than the herbaceous vege- shrubs. 
tation. ° 
. Tree stratum. 5. Tree stratum; inhabitants of trees. 
Los) 
On 
