ON A MINUTE NOSTOC WITH SPORES, ETC. Sfl 



he doubts not the tenability of the assumption that every 

 Collema in free nature is a " Nostoc," thus made the nidus 

 for the development of the spores, evolved, of course, from a 

 preceding "Nostoc^' so naturally inoculated (as one might 

 say), that is to say, in other words, a preceding compound 

 organization which is known as " Collema." Such is, as 

 briefly as possible, the result of Keess's experiences, and the 

 views beholds ; it would lead too far to endeavour to go more 

 closely into the arguments and statements of Reess and 

 Schwendener — those of the latter applied to the Lichens at 

 large, not the Collemacese only — but it may not be wholly 

 without use to have directed attention to their remarkable 

 memoirs. 



Basing his opinion, as it would seem, at least mainly, upon 

 the result of the experiments of Professor Reess alluded to. 

 Professor Cohn^ would exclude the Collemaceaj from the 

 Lichens, which (without these), as a class, he would retain, 

 remarking that " he knows no Algae which could be trans- 

 formed by the influence of a fungus into Usnea, Cladonia, 

 Cetraria, &c., but that it appears to him that the parasitism 

 has been rendered by De Bary and Reess extremely probable 

 for the ' Collemacese.'" 



ScliAvendener himself, in his later memoir," figures certain 

 Nostoc specimens whose gelatinous matrix is seen to be 

 penetrated by Avhat he denominates fungal threads (Pilsfaser), 

 and these he points to as evidence of the truth of his view ; 

 that is, that they become the hypha, and that the phenomena 

 of growth thereby induced absolutely convert the " Nostoc" 

 into " Collema ;" and he firmly holds his figures prove the 

 case. Now, Beess, referring to these very figures, conceives 

 the fungal threads depicted must be strictly those of a 

 (destructive) fungus — a mould, in point of fact ; he thinks, 

 indeed, they may be anything whatever, but one thing clearly 

 he avers, be they what they may, they are by no means a 

 Collema-hypha, founding his opinion, of course, upon the 

 knowledge gained from his recently conducted experiments. 

 So that Avhatever may be the opinion of other observers as to 

 the result of the researches of Reess, at least the examples 

 adduced by Schwendener relating to Collema, it would 

 appear, must be held as inconclusive. 



It may, perhaps, be not inopportune to observe that, as 

 must be well known, the gelatinous masses of those Alga3 

 which grow on wet rocks and such situations, be they 



' Prof. Dr. r. Colin, " Conspectus Pamiliarum cryptogamarum secundum 

 metliodum naturalem dispositaruna," in ' Hedwigia,' No. 2, 1872, p. 17. 

 = *Die Algentypen,' &c., pp. 28, 99, t. ii, ff. 13—15. 



