22 FIRST STEPS IN GENERAL KNOWLEDGE. 



seeds, and the lichen is in perfection when so 

 adorned. Some of these shields, as you remember, 

 lie flat upon the lichen, others are elevated on 

 little stalks. They are always best developed in 

 places fully exposed to the light ; hence it is of 

 very little use to search for shield-bearing lichens 

 in shady groves or in the dark clefts of rocks. 

 You have proved how well lichens can be kept, 

 without the trouble in drying which you have 

 with other plants. Some of those in my cabinet 

 were gathered twelve years ago, and are very 

 little altered : and I have seen older collections in 

 fine preservation." 



