442 BOTANICAL GAZETTE [JUNE 
Plants of the eastern peat bogs find difficulty in absorbing water, 
possibly because of toxic substances in the soil, and these are cuti- 
nized, not hairy (except Ledum). 
KERNER emphasizes the prominence of hairy plants in the Medi- 
terranean region and notes that they are not so numerous in the 
adjacent steppe region, because “in the steppes and deserts the dry- 
ness of the summer is greater, and even thick hairy coverings are not 
always a sufficient protection against this dryness; and also because 
in some districts the dry period passes directly into a severe winter.” 
In the Mediterranean region, as the dry summer follows the rains of 
winter and spring, “their transpiration is very active in consequence 
of the rapidly increasing temperature of the air, but the saturated 
soil provides a sufficient substitute for the evaporated water.” Toward 
midsummer, as the drought increases, “if such a plant is to be 
protected from drying up, its transpiration must be lessened. This 
is effected by various protective arrangements, but best of all by a 
thick coating of hair.” Very interesting are the biennial plants 
cited by KeRNER. The leaves of these plants formed the first year 
must pass through the summer and so are abundantly hairy, while 
those of the leafy flowering shoot the second spring are green instead, 
because this shoot dies before the summer begins. ‘The whole of 
KERNER’S account of Mediterranean plants is just what we should 
expect from the standpoint of the present experiments. There is 
sufficient water in the soil at all times to make moderate transpiration 
possible even insummer. At times when this supply is at its minimum 
and when the sun and wind are exceptionally drying, the leaves are 
protected from too excessive transpiration by the hairy covering. 
GoEBEL,’° in describing the flora on the Venezuelan Andes between 
tree line and snow line, remarks on the great number of hairy plants. 
The white-woolly rosettes of certain species are characteristic of the 
landscape. The climate here is subject to great and frequent change 
from rain, snow, or fog, to sunshine and an exceedingly drying 
wind. The temperature varies also from o° to 18°. The soil con- 
tains plenty of water, with frequent puddles standing on the surface. 
The soil is cold and absorption is slow, but the transpiration at times 
10 GOEBEL, K., Die Vegetation der venezolanischen Paramos. Pflanzenbiolog- 
Schilderungen 2:1. 1893. 
