236 SCYTONEMEiE. 



respond with the genus as defined by Mr. Berkeley or 

 myself, neither does his genus Siros^/phon answer to the 

 genus Hassallia, formed by Mr. Berkeley for those species 

 hitherto associated with the genus Scytonema, but which the 

 definition of that genus, as it at present stands, does not 

 embrace. 



The following is Kiltzing's definition of Scytonema : — 

 " Trichomata vagina duplici, firma crassiuscula colorata 

 arete inclusa ramosa ; rami ex continuatione trichomatis in- 

 terni et prolongatione vaginae oriundi, non basi iis discreta. 

 Spermatia ex articulis intumescentibus progenita." 



In the genus as thus characterised, Kiitzing includes the 

 following British species. Scytonema (sruginco-cinereum 

 ( Ocellatoria rupestris, Grev. Scot. Flor. Turf. 246. ?), *S'. my- 

 ochrous, S. turfosum, and iS. coinpactiim. Now out of these 

 fovu' species there is but one which could be received into 

 the genus Scytonema of Mr. Berkeley, and that one is Scyt. 

 myoclirous. It is clear, therefore, that there is no correspond- 

 ence between the genus Scytonema of Berkeley and that of 

 Kiitzing. 



1. Scytonema hibernicum Hass. 



Plate LXVIII. Fig. 1. 



Char. Filaments of considerable diameter. Cells about as 

 long as broad, issuing in pairs at rigid angles with the 

 stems. 

 Scyt. hibernicum Hassall, MS. 



Hab. On a clayey bank, co. Antrim, Ireland : il/r. 

 Moore. 



Of this beautiful species I have seen but a single specimen. 

 It was sent to me by INIr. Moore, with the name of Scyt. 

 ocellatwn upon it, with Avhich plant however it has no affi- 

 nity. The cells are of exactly the same form as in Scy. 

 myochrous, from Avhich it differs principally in being alto- 

 gether laro-er. 



