Archer — On A^iothecia in Algcp. 87 



He justly observes they should begin the series, amongst the bluish- 

 green filamentous fonns, by reason of the well-expressed contradistinc- 

 tion offered by them between apex and base, also by reason of their 

 being marked by a formation of true branches, as well as, in their 

 higher representatives, showing an evident accession to their thickness 

 by subsequent growth. Possessing these specialities, they at the same 

 time, however, show an unmistakable affinity on the one hand to the 

 8cytoyieme(B and RivulariecB in the common possession of " heterocysts " 

 and an apical growth, and on the other to the Nostocliace(B, which, 

 wanting apical growth, form a transition to the OsciUariece. 



Prior to the propounding of the new hypothesis, however, certain 

 of these forms, which, if met with without apothecia, would have been 

 referred to the genus Scytonema, had been found with apothecia and 

 thereupon new genera were formed for them by Itzigsohn and IS^ylander 

 under the names Efhehella, Itzigsohn, and Gonionema, I^yl. (or Tlier- 

 mutis, Pr. ?). In fact, they seem to have regarded the ''baiTen" and 

 the "fertile " plant as each belonging to distinct genera, even as ap- 

 pertaining to different classes — that is, that the "barren" was to be 

 accounted an " alga " and the " fertile " a " lichen." 



Of course, had Schwendener's view, but comparatively lately put 

 forward, been then current, and had it been adopted by the discoverers 

 of those apothecia-bearing SironifJionacece, and Scytonemacecs, the case 

 would have been different: the new name would in that case have 

 been, as I take it, understood to be applied to the ' ' new ascomyce- 

 tous parasite," within the Sirosiphon, or the Scytonema — the double 

 names should still pass current, for, in that case, they would stand for 

 essentially distinct things, and no less so because these occur sometimes 

 living in consort and in a state of mutual physiological dependence. 



The present communication, therefore, loses much of the signifi- 

 cance it might have been at least temporarily held to possess, from not 

 being brought out at the time the observations were made, but after 

 the new theory had been not only propounded, but had gained a large 

 amount of currency. 



Nevertheless, although more superficially put forward than if I had 

 made the matter public at the time of the obsei'vations, and when these 

 were fresh in my mind, this will, I think, be the first record of " apo- 

 thecia " being noticed in at least five fresh fonns or species referrible to 

 separate "genera" {Scytonema, SirosipJion, Stigojiema) in the algal point 

 of view. If this record had been brought out at that time, indeed, it 

 would have pointed, as I should have taken it, to the assumption that 

 these, in place of genera of algae, were in truth genera of lichens — not 

 "new" lichens, but lichens not taken pre\iously "in fruit." 



"With respect to Ephebe and Spilonema, Schwendener argues, that 

 a genetic connexion between the hyphae and the gonidia is impossible. 

 Por the whole chain of gonidia leads onwards to the apical cell, by the 

 unlimited subdivision of which new cells continuously originate, which 

 are themselves again to be regarded as mother-cells (in those genera) of 

 so many groups of gonidia. The assumption of a new formation of 

 gonidia by growing-nff from the hypha has no justification whatevor ; 



