406 BOTANICAL GAZETTE [JUNE 
MODE OF DISSEMINATION. 
By all means the commonest and most effective means by 
which Ramalina reticulata is reproduced and distributed is by 
larger or smaller pieces being torn by the wind from plants firmly 
attached, and carried to trees or shrubs, on the bare, rough 
branches of which the fragments catch and stay (fig. p. 405). As 
will be shown later on, this lichen softens to a remarkable degree 
when wet, it absorbs much water and greatly increases in weight, 
and its netted structure and branching habit cause it to be easily 
torn as it hangs down like a soft, delicate piece of gray-green 
lace, always longer than it is broad. When dry, it is hard, stiff, 
tenacious, and elastic, not readily broken by the wind. When 
wet, it is soft, pliant, not especially tenacious or elastic, and it is 
much heavier. As a rough index of the increase in weight dur- 
ing a hard and protracted rain the following figures will serve. 
Fragment air dry weighed - ener 0.499 8T- 
“ soaked 15 min. in cold? water and surface dried 
by filter paper, weighed - s 
Weight wet: weight dry = 2.04:1. 
This increase in weight is less than that which would occur in 
nature, for more water would there adhere to the surface of the 
lichen than was left by the filter-paper. The increase in weight 
is furthermore unaccompanied by any immediate increase 17 
strength,3 for it is impossible that growth should occur 5° 
promptly or so rapidly as to keep pace with the increase ! 
weight, although the wetting and consequent increase in weight 
take place more slowly in nature, even in a hard rain, than 
when the lichen is immersed in water in the laboratory. 
The rains come only in winter, when the branches of many 
trees and shrubs are bare of leaves, and roughened by buds and 
barky excrescences. The rains are usually accompanied by wind, 
often high wind. It is therefore easy to see that the tearing 
away by the wind of fragments from the soft, heavy, pendant 
1.020 gr. 
*Cold water to avoid possible solution of gelatinous matter. 
3 For the actual decrease in strength see p. 415. 
- s 
