1881.1 



MICEOSCOPICAL JOUKNAL. 



169 



An Introduction to the Study 

 of Lichens.* 



BY THE REV. W. JOHNSON. 



The group of plants, which is to 

 occupy our consideration in this 

 paper, has until recently been re- 

 garded as the "approbria" of our 

 Cryptogamic Flora ; and these hum- 

 ble members of the vegetable king- 

 dom may still be so regarded by 

 many people. But, when we become 

 acquainted with the Lichens, when 

 we take time to behold their hidden 

 beauty, to understand their structure, 

 their habits, uses and modes of 

 growth ; when we feel the thrill of 

 enthusiasm which they can impart, 

 and when the frail things, dried in 

 the herbarium, gather around them- 

 selves some of the sweetest associa- 

 tions of our life — associations redo- 

 lent of the woods, the heaths, the 

 mountains and the shore ; then, dis- 

 regard of them, much more despising 

 them, becomes a matter of surprise. 

 Disregard, or despicable feelings in 

 relation to Lichens, may arise from 

 ignorance ; but they cannot arise 

 from any lack in the plants them- 

 selves of those qualities which create 

 and sustain interest ; nor, from any 

 surrounding difficulties which are in- 

 superable to a pleasant, profitable 

 and useful study of them. There are 

 difficulties in the study of Lichens, 

 and perhaps, some which are pecu- 

 liar ; but, as in all things else, an un- 

 enlightened imagination magnifies 

 them. The chief obstacles here are 

 two. These are the terminology and 

 the determination, or the distinction 

 of the species and varieties. The 

 first is the common tax of knowledge 

 in all her departments. You must 

 master the phraseology before you 

 can know the subject. The second is 

 a difficulty which now, when it is the 

 greatest on account of the many 

 forms discovered, the differences of 

 which are small ; yet, it is the more 



* From the Northern Microscopist. The 

 illustrations to accompany this article will be 

 printed with the continuation next month. 



easily overcome, because the very 

 growth of our Lichen-flora has re- 

 sulted in a more natural and com- 

 prehensive classification, as well as in 

 a better and more certain method of 

 study. As in other departments of 

 nature, the microscope has here come 

 to our aid ; and now, by comparing 

 the internal structure, the shape, size 

 and color of the spores, with the out- 

 ward features of the plant, the deter- 

 mination of species is more easily 

 and correctly attained, than when 

 such determination was made simply 

 by observing the external character- 

 istics alone. Beyond these two checks, 

 the path in lichenology is compara- 

 tively smooth, and abundantly health- 

 ful and enjoyable. 



Lichens are a class of plants in the 

 secondary division of the vegetable 

 kingdom. They belong to the Cryp- 

 togamia or flowerless plants. Their 

 position in that division is between 

 the fungi on the one hand, and the 

 algae on the other. The difference 

 between the Lichens and those two 

 adjoining classes is not so great that 

 their boundaries are unquestioned. 

 Nor yet, are their affinities so close 

 that the Lichens are not clearly dis- 

 tinguished between the two. Nature 

 has no sharp and fast lines in her di- 

 visions. Her boundaries generally 

 overlap, and it is so here. The 

 Lichens run into the fungi in the 

 corticulose Verrucareae, and into the 

 algae in the gelatinous Collemacei. 

 In a new text book on botany,* re- 

 cently translated into our language. 

 Lichens are no longer regarded as 

 having a distinctive existence. Their 

 position as a separate class of plants 

 is spoken of as a thing of the past. 

 They are here placed in the order of 

 Ascomycetes amongst the fungi. 

 This new departure in relation to 

 Lichens, which, to say the least of it, 

 is somewhat presumptuous as well as 

 premature, is founded upon a theory 

 propounded by Schwendener some 



* Text Book of Botany. Prank & Vines, 

 1880. 



