74 ROMANCE OF LOW LIFE AMONGST PLANTS. 



its service. It surrounds them as a spider its prey, 

 with a fibrous net of narrow meshes, which is gradu- 

 ally converted into an impenetrable covering ; but 

 whilst the spider sucks its prey and leaves it dead, 

 the fundus incites the alg^e found in its net to more 

 rapid activity, nay, to more vigorous increase." This 

 may be all very poetical, but it is not very explicit, 

 and needs a commentary. This we furnished very 

 many years since, and it has never been called in 

 question, but corroborated, to the following effect : 

 that the two great points sought to be established 

 are these, that what we call lichens are compound 

 organisms, not simple, independent vegetable entities; 

 and that this compound organism consists of uni- 

 cellular algse, with a fungus parasitic upon them. 

 The coloured gonidia which are found in the sub- 

 stance, or thallus, of lichens, are the supposed algae, 

 and the cellular structure which surrounds, encloses, 

 and imprisons the gonidia, is the parasitic fungus, 

 which is parasitic on something infinitely smaller than 

 itself, and which is entirely and absolutely isolated 

 from all external influences. In plain words, the 

 gonidia are algae, and all the rest of the plant is 

 fungus. 



This hypothesis has so few adherents, and those 

 few of such little eminence or authority, that it would 

 be quite unnecessary and impolitic to reopen the dis- 

 cussion or repeat the arguments against it, which 

 have never been successfully controverted. As a 

 mere historical summary, it may be advisable to state 

 a little more definitely what were the points in dis- 

 pute, and, in doing so, to intimate, as a matter of fact, 



