5 
mentioned do not permit of its satisfactory determination. Very 
likely it was not what we call a Lichen, as our plants seem to have 
been known to the Greeks under the name Sflachnon, Phascon, 
and sometimes 4ryon, names which now, curiously enough, are 
applied to genera of true mosses. 
In attempting to describe as briefly as possible the leading 
features in the appearance and structure of Lichens, it seems 
advisable to depart in some measure from the usual arrangement 
in botanical treatises, and to avoid, as much as possible, the use 
of technical language; and perhaps no better method can be 
adopted than to suppose ourselves engaged in collecting Lichens 
somewhere in the immediate neighbourhood of Ambleside, and to 
discuss such plants as we should be likely to meet with. 
The best time for collecting Lichens is a bright day that has 
followed some rainy weather. It does not do very well to gather 
them when everything is saturated, for the substance of these plants 
swells with moisture, and when the weather is very wet they swell 
so much that their shape is considerably altered. But a change 
greater than that of shape takes place in such circumstances in their 
colour. In wet weather, their distinctive tints are for the most 
part lost, as the moisture renders their outer layers translucent, and 
permits the green colour of the internal cells to shine through and 
thus modify and obscure the usual colours of the plants. Neither 
is a very dry day the best that can be chosen, especially if it has 
been preceded by any long continuance of drought. Under such 
circumstances, Lichens become very brittle, and_ satisfactory 
specimens of some species cannot be obtained, as they break in 
pieces either while being removed, or in taking them home. 
Speaking of the influence of the weather induces me to notice a 
peculiarity of Lichens which is sufficiently remarkable. It is that 
they lead a sort of intermittent life. In moist weather growth goes 
on continuously, but with the occurrence of dry days all progress 
ceases fora time. The plants dry up and become as it were dead, 
so that one may take many of them, and crumble them to pieces 
in one’s hand. Their life and activity, however, are only arrested. 
On the recurrence of favourable weather, they awaken to new life 
