124 W. ARC U Ell. 



liyphce has been generally accepted up till about three years 

 ago. According to Bayrhoffer the threads of the * fibrous 

 stratum' swell at the top, which swellings afterwards become 

 ' male gonidia.' That the correctness of the observation may 

 be strongly doubted, and must rather be credited to the ob- 

 server's fancy, every one will agree with me who is acquainted 

 with Bayrhoffer's work, in which are to be found the most 

 extraordinary ideas about lichens. Thus, for example, accord- 

 ing to Bayrhoffer, the thallus is composed of a male and a 

 female stratum. 



As regards Speerschneider, he stated that in Hagenia 

 ciliai^is at the place of transition between cortical and medul - 

 lary hyphae, gonidia originate on the hyphae, which, apart from 

 the green colour, very much resemble at first young hypha- 

 branches, besides which larger gonidia occur intimately united 

 with the hyphae, which is a further reason for assuming that 

 the gonidia originate from these. In his work he subsequently 

 assumes the same mode of origin of gonidia for other lichens ; 

 inRamalina several gonidia are said to originate from one 

 hypha-swelling, and in Peltigera to be formed in the hypha. 

 The statement is also especially noteworthy that in Hagenia 

 some gonidia, amongst which very young and minute ones 

 contain no chlorophyll. How is this to be reconciled with 

 his just quoted opinion, expressed a year earlier, that the 

 existence of their colouring svibstance alone distinguishes the 

 young gonidia from commencing lateral branches ? 



Th. M. Fries and J. Miiller last year have cursorily 

 made known some observations of the origin of the gonidia 

 from the hyphse, without, however, giving figures or any 

 description of their mode of observation.^ 



" My own researches, which were chiefly carried out with 

 Xanthoria parietina, and the conclusions deduced therefrom, 

 briefly amount to this : — 



The origin of the gonidia from the hyphse will be clearly 

 proved only when cells still uncoloured green are found on 

 the hyphae, and which can be recognised as gonidia by the 

 cellulose reaction of their walls. The occurrence of minute 

 but already distinctly green gonidia united with liypha- 

 branches at least furnishes no proof, because (1) Schwendener, 

 more than ten years ago, showed that the so-called stipites 

 might be the result of the growth of the hyphae against the 

 gonidia ; (2) gonidia are to be found (which I have succeeded 

 in doing many times) which are furnished with more than one 

 stipes. Just as little is it possible to recognise by the form 



» • Mora/ 1872, p. 90. Vide supra. 



