14 FUNGI. 



genera, must, however, be considered as connecting TricJiogastres 

 with lichens, and the question cannot be considered as satis- 

 factorily decided till a series of experiments Las been made on 

 the germination of lichen spores and their relation to free alga3 

 considered identical with gonidia. Mr. Thwaites was the first 

 to point out* the relation of the gonidia in the different sections 

 of lichens to different types of supposed alga?. The question 

 cannot be settled by mere a priori notions. It is, perhaps, 

 worthy of remark that in ClijonypTie Cartel i the threads grow 

 over the cysts exactly as the hypha of lichens is represented as 

 growing over the gonidia. 



Recently, Dr. Thwaites has communicated his views on one 

 phase of this controversy,-)- which will serve to illustrate the 

 question as seen from the mycological side. As is well known, 

 this writer has had considerable experience in the study of the 

 anatomy and physiology of all the lower cryptogamia, and any 

 suggestion of his on such a subject will at least commend itself 

 to a patient consideration. 



" According to our experience," he writes, " I think parasitic 

 fungi invariably produce a sad effect upon the tissues they fix 

 themselves upon or in. These tissues become pale in colour, 

 and in every respect sickly in appearance. But who has ever 

 seen the gonidia of lichens the worse for having the 'hypha' 

 growing amongst them ? ' These gonidia are always in the 

 plumpest state, and with the freshest, healthiest colour possible. 

 Cannot it enter into the heads of these most patient and ex- 

 cellent observers, that a cryptogamic plant may have two kinds 

 of tissue growing side by side, without the necessity of one 

 being parasitic upon the other, just as one of the higher plants 

 may have half a dozen kinds of tissue making up its organiza- 

 tion ? The beautifully symmetrical growth of the same lichens 

 has seemed to me a sufficient argument against one portion 

 being parasitic upon another, but when we see all harmony and 

 robust health, the idea that one portion is subsisting parasitically 

 upon another appears to me to be a perfect absurdity." 



* "Annals and Magazine of Natural History," April, 1849. 

 + In "Gardeners Chronicle" for 1873, p. 1341. 



