I 



Repoyt of Fauna and Flora Committee — Irish Ph<Bophycece. 455 



Petrospongium, IS'ag. 



P. Berlcele.yi,^^Z- H ^- 12 N. 14 K 



Now known with both unilocular and plurilocular sporangia. 



Leathesia, J. E. Gray. 



Z. difformis, Aresch. 10-14. 



Phaeostroma, Kck. 



Ph. pustulosum, Kck. 12 1^. 



Epiphytic on young Laminaria saccharina. 



Cohort II. — Laminarin^. 



Order I.— Scttosiphonace^. 

 Phyllitis, Kiitz. 



Ph. Fascia, KUtz. 



This species has a dark olive discoid root, thus being easily 

 distinguishable from the Laminarias with branching fila- 

 mentous root. It has plurilocular sporangia. 



Scytosiphon, C. Ag. 



S. lomentarius, J, Ag. 10-14. 



Order II. — Chordace^. 

 Chorda, Stach. 



The unilocular sporangia are distributed over the whole 

 surface. Buffham discovered the plurilocular sporangia, on 

 plants with twisted thallus, in Ch. Filum. 

 Ch. Filum, Stackh. 10-14. 

 Ch. tomentosa, Lyngb. 12. 



Order III. — Laminaeiace^. (The Kelp-weeds.) 



Laminaria, Lamx. 



Possesses unilocular sporangia only, variously distributed in 

 sori. 

 L. saccharina, Lamx. 10-14. 

 /. Phyllitis, Le Jol. 12. (Mgvet. Heligoland, p. 255.) 



Kuckuck ^regards this variety as likely, by its intertidal 

 habitat, to remain sterile. 



