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The Museum Gazette 



did, as forming a natural group of plants. One species of 

 algal may serve as a base for several lichen-fungi. It would 

 appear that, with one exception, 1 as far as is known at pre- 

 sent, lichen fungals have become so highly specialised that 

 they cannot leave their host and grow independently ; they 

 are like the Amazon ants, which have become so dependent 

 upon their slaves that they cannot exist without them, the 

 slaves making the nest and even feeding the young. 



Appreciating them by their superficial characters we may 

 arrange the lichens on the bole into four distinct groups. 



Firstly, we have the Leaf-like lichens, which form patches 

 spreading outwards from the centre of attachment in a more 

 or less circular manner. The most noticeable, being by far 

 the largest, forms large yellowish-green patches, the lobed 

 margins of which are smoother than the centres. Its scientific 

 name is Parmelia capevata. The smaller patch of a greyish hue 

 without any trace of yellow is the P. perlata. It is quite as 

 common as the preceding kind. Here we have a patch of 

 P. olivacea, a dark olive-brown insignificant looking plant, 

 always looking as if very tightly pressed or flattened upon the 

 bark. The Parmelias are much used for dyeing. 



Secondly, we may note the Beard-like lichens. Look at 

 this one. The branches are of variable length and thickness, 

 the main one being the largest, and all are round. Some- 

 times it hangs from the trunk, occasionally it grows erect. 

 It is the " beard moss" and "tree moss" of the poets, the 

 Usnea barbata of the lichenist. It is very common and widely 

 distributed. In some countries it is used as fodder, and for 

 producing a yellow dye. Another shaggy greenish-white 

 lichen, equally common, has flattened instead of rounded 

 branches, pitted with shallow depressions. It is known to 

 botanists as Evernia pnmastri. Examine a tuft carefully, you 

 will see it is attached to the bark at one point only. In 



'The Cora lichen of Brazil has been shown to result from the conjunction 

 of one of the Telephoreae group of fungi with the cells of a Chroococcus. 



