680 SUMMARY OF CURRENT RESEARCHES RELATING TO 



L. sophodes, L. coilocarpa, and L. csesio-rufa ; witli Trentejpohlia — 

 Opegrapha vulgata, GrapMs elegans, and Verrucaria muralis. 



Tlie development of Physcia pnrietina is described as follows: — 

 Two spores only were sown, with about thirty Protococcv s-cells. The 

 germinating filament from the sjiore elongates at its extremity; the 

 terminal portion swells, often becomes cut off by a septum, and puts out 

 lateral swellings which develope into slender branches ; these envelope 

 the algae, until the latter are completely surrounded by hyphte of three 

 kinds, viz. swollen filaments, clamp-filaments in immediate contact with 

 the algae, and elongated filaments which extend towards the periphery 

 apparently in order to search for fresh algae ; the swollen hyphae are the 

 origin of the pseudo-parenchyme of the lichen. 



It is frequently asserted that a constant and essential difference 

 exists between fungi and lichens in the much greater thickness of the 

 cell-walls of the latter; but M. Bonnier has watched the gradual 

 thickening of the walls as the hyphae of the lichen come in contact with 

 the nourishing algae; it is not strongly manifested until the pseudo- 

 parenchyme is already partly formed. 



Development of Lichens on the Protoneme of Mosses.* — M. G. 

 Bonnier has observed that when the spores of lichens germinate in con- 

 tiguity with the protoneme of a moss, they may completely invest it and 

 carry on a parasitic existence upon it. He has succeeded in obtaining a 

 parasitism of this kind by inducing the spores of Parmelia aijpolia and 

 physodes to germinate on the protoneme of such mosses as Eypnum 

 cupresdforme, Barhula muralis, Funaria hygrometrica, Mnium hornum, 

 Dicranella varia, and PJiascum cuspidatum. The lichen-hyphge will in 

 such circumstances completely envelope the protoneme and ultimately 

 destroy it, but without producing any fructification. But the protoneme 

 will sometimes produce buds or propagules with very thick cell-walls 

 which offer a resistance to the attacks of the lichen-filaments and preserve 

 the life of the moss. This occurs specially with Mnium hornum. The 

 lichen-spores will also sometimes germinate on the leaves of the moss, 

 but will not develope into a perfect lichen unless they meet with algal 

 gonids. 



Pilophorus.j — Prof. T. M. Fries unites together the three species 

 of this genus of lichens previously known, viz. P. rohustus, acicularis, 

 and cereolus, and describes a new species from Vancouver's Island, 

 P. clavatus, distinguished by the very unusual form of the apotheces, 

 which are no less than four or five times higher than broad. 



Fungus-parasites of the Alder. | — Prof. E. Sadebeck states that the 

 grey spots on the leaves of Alnus incana are produced by Exoascus 

 epipTiyllus — identical with Taphrina horealis — which also settles on leaves 

 of A. glutinoSa already attacked by E. alniiorquus, producing its asci 

 among those of the latter. The scales of the female catkins of both 

 species of alder are subject to the attacks of an undescribed Exoascus, 

 which the author proposes to call E. amentorum, resembling Ascomyces 

 endogenus, but marked as belonging to Exoascus by its abundant 

 mycele. 



* Eev. Gen. de Bot. (Bonnier"), i (1889) pp. 165-9 (1 pL). 



t Naturvetensk. Studentsiillsk. Upsala, March 27, 1888 (1 fig.)- See Bot. 

 Centralbl., xxxviii. (1S89) p. 7«4. J Ber. Gesell. Bot. Hamburg, 1888, p. 90. 



