282 Mr George Traill on the 



PYLAIELLA, Bory. 



50. Pylaiella littoralis (Linn.), Kjell. {Ectocariyus littoralis, Lyngb.) 

 Epiphytic on Algre in pools between tide marks ; also on exposed 



rocks. At all seasons. Fruit in summer. Host plants : Fuciis 

 serratus, Fucus vesiculosus, Fucus platycarjjus, Scytosi2)Jion lomen- 

 tarius, Fohjsiphonia fastigiafa, Halidrys siliquosa, Cladophora 

 rupestris, CalUthamnion arhuscula, Laminaria digitata, Uloa 

 laduca, Linn., Chcetomorpha Melagonium, Rlwdymenia palmata, 

 Polydpjlionia fihrillosa. 



Family.— SPHACELARIACE^. 

 SPHACELARIA, Lyngb. 



51. Sphacelaria cirrhosa (Roth), Ag. 



Epiphytic on Algae in pools at many places at and above 

 half-tide level. All the year. Fruit in June and July ; propagula 

 in July. Host plants : Halidrys siliquosa, Gladopliova rupestris, 

 Polysiplionia fihrillosa, Polyides rotundus, Fucus vesiculosus, Poly- 

 siphotiia nigrescens, Cladostephus spongiosus, Corallina officinalis, 

 Gelidium corneum. 



52. Sphacelaria radicans (Dillw.), Harv. 



Usually on sand-covered rocks near low-water mark. All the 

 year. Fruit in winter. 



52a. Sphacelaria radicans (Dillw.), Harv., var. olivacea (Dillw.), Batters. 

 Usually in velvety patches on rocks near high-water mark, 

 accompanying Rlwdocliorton Rotliii. All the year. Unilocular 

 pedicellate sporangia in winter. Eather rare. 



53. Sphacelaria tribuloides, Menegh. 



Occurs in a round basin-like pool at rather a high level, a little 

 to the west of the ladies' bathing pool, west of the castle. It 

 accompanies Sphacelaria cirrhosa, but does not seem to be epiphytic. 

 Found by Mr Holmes in 1884. 



CHLffiTOPTERIS, Kiitz. 

 53a. Chsetopteris plumosa (Lyngb. ), Kiitz. 



Occurs in considerable abundance in pools at about half-tide level, 

 especially at the west of the castle. Perennial. Fruit in winter. 

 (G. W. T. 1890.) 



CLADOSTEPHUS, Ag. 



54. Cladostephus spongiosus (Lightf.), Ag. 



Common on rocks and in pools near low-water mark. Perennial. 

 Fruit in winter. 



Family.— EALFSIACE^. 

 RALFSIA, Berk. 



55. Ralfsia verrucosa, Aresch. 



Common in shallow pools between high-water mark and half-tide 



