930 RECORD OF CURRENT RESEARCHES RELATING TO 



are sufficiently well figured in ' Tul. Mem. Lich.,' t. 3, f. 3), and 

 behold the whole pi'ocess of evolution from tlie germinating spore to 

 the perfect thallus, and at length to the formation of the perfect 

 apothecium. All of these are seen to be formed of themselves, that 

 is, by an innate power or impulsion of procreation, which is inherent 

 in the sjiore, the only aiding materials being those lent by the atmo- 

 sphere, especially rain-water. Upon the very pure glassy substratum 

 where these vital phenomena go on, no trace of any Protococcus 

 (or Pleurococcus), nor of any element of a heterogeneous thallus 

 can be detected in the vicinity, although innumerable examples of 

 such germinations have been examined in very favourable circum- 

 stances, especially in Lecanora (jalactina Ach., Lecanora exicjua Ach., 

 and Lecidea alboatra Hoffm., growing upon glass. The prothalline 

 commencements of Lecanora exigua radiate dendritically around the 

 spores, and are of a blackish colour, forming the hypothallus, in which 

 minute, cellulose, thalline glomeruli are produced, presently exhibiting 

 gonidia forming themselves in the cells (as in Tul, Mem., I. c.) ; 

 often also we see apothecia produced even in a very young plant. 

 The same is the case with the beginnings of Lecanora galactina ; * 

 but here the hypothallus is white, consisting of white, byssine, 

 appressed filaments, laterally apposite and contiguous. All these 

 hypothalli are very closely agglutinated to the glass ; and there are 

 no traces whatever of any Protococci in connection with them." 



These observations of themselves (Mr. Crombie says) in connection 

 with Vitricole Lichens (which, in this country, he has only observed 

 on broken pieces of bottles on garden-wall tops, chiefly in Scotland) 

 are amply sufficient to show how untenable is Schwendener's hypo- 

 thesis, which, in the concluding words of Nylander's paper, is thus 

 " reduced to the nothingness from which it ought never to have 

 emerged." 



Parasitism of Lichens on Mosses.t — II. Zukal, having observed 

 the frequent occurrence of luxuriant lichen-growths in the midst of 

 tufts of moss, has determined the cause to be a parasitism of the lichen 

 on the moss. 



The stem and leaves of Plagiotliecmm sylvaticum were penetrated 

 in all directions by thehyphte of the thallus of a Pertnsaria and those 

 of Hypmm splendens by a Lep-aria. The stems of a plant of Pohjtri- 

 chuni commune, up to the rosette of leaves, were found to be infested 

 with minute patches of the thallus of a Cladonia. In one case the 

 lichen had attached itself to the apex of the leaf of the Pohjtrichum, 

 and completely penetrated the leaf with its rhizines. The gonidial 

 layer of the lichen was in these cases normally developed. 



Colorific Properties of Lichens. t— The subject of the colouring 

 matters contained in lichens — to which Dr. Lauder Lindsay directed 

 attention in 1858-5 — has recently reacquired, he says, considerable 

 interest in connection with the introduction of colour-tests, as 



* This Mr. Crombie says he can entirely corroborate from his own observations 

 on this species, as growing on mortar in tlie north suburbs of London, 

 t ' Oesterr. Bot. Zeitschr.,' xxix. (1879) p. 189. 

 j ' Grevillea,' viii. (1879) p. 2r). 



