NATURE 01' FUNGI. 11 



them, as a spider does its prey, with a fibrous net of narrow 

 meshes, which is gradually converted into an impenetrable 

 covering. While, however, the spider sucks its prey and leaves 

 it lying dead, the fungus incites the algae taken in its net to 

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

 hypothesis, ushered upon the world with all the prestige of the 

 Professor's name, was not long in meeting with adherents, and 

 the cardinal points insisted upon were— 1st. That the generic 

 relationship of the coloured "gonidia" to the colourless fila- 

 ments which compose the lichen thallus, had only been assumed, 

 and not proved ; 2nd. That the membrane of the gonidia was 

 chemically different from the membrane of the other tissues, 

 inasmuch as the first had a reaction corresponding to that . ot 

 algsa, whilst the second had that of fungi ; 3rd. That the 

 different forms and varieties of gonidia corresponded with 

 parallel types of algas ; 4th. That as the germination of the 

 spore had not been followed further than the development of a 

 hypothallus, it might be accounted for by the absence of the 

 espential algal on which the new organism should become para- 

 sitic; 5th. That there is a striking correspondence between the 

 development of the fruit in lichens and in some of the sporidii- 

 ferous fungi (Pyrenoniycetes). 



These five points have been combated incessantly by lichen- 

 ologists, who would really be supposed by ordinary minds to be 

 the most practically acquainted with the structure and develop- 

 ment of these plants, in opposition to the theorists. It is a fact 

 which should have some weight, that no lichenologist of repute 

 has as yet accepted the theory. In 1873 Dr. E. Bornet* came 

 to the aid of Schwendener, and almost exhausted the subject, 

 but failed to convince either the practised lichenologist or 

 mycologist. 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 unicellular algae, with a fungus parasitic 

 upon them. The coloured gonidia which are found in the 



* Bornet, (E.), " Recherches sur les Gonidies des Lichens," in " Ann. des Sei. 

 Nat." 1873, 5 ser. vol. xvii. 



