SEAWEEDS OF THE BLACKWATER ESTUARY 321
Calothrix pulvinata ((Mert.) C. Ag.) Born. et Flah. Osea Island, Batters
(1897).
Calothrix scopulorum ((Webb et Mohr) C. Ag.) Born. et Flah.
Clacton, Batters (1894).
Isactis plana ((Harv.) Thur.) Born. et Flah. Blackwater Estuary,
Batters (1894).
Rivularia atra (Roth.) Born. et Flah. Felixstowe, Batters (1894).
Scytonemataceae
Plectonema battersii Gom. Canvey Island, Carter (1933).
Stigonematales
Nostochopsidaceae
Mastigocoleus testarum (Lagerh.) Born. et Flah. Maldon, Batters
(1894).
Phaeophyceae
Ectocarpales
Ectocarpaceae
Acinetospora crinita (Marv.) Kornm. River Blackwater (East Mersea
Saltmarsh), G.M.M., 1963.
Ectocarpus arctus Kutz. Walton, Harwich, Dovercourt, Clacton and
Felixtowe, Batters (1894) (as E. confervoides and E. siliculosus);
River Blackwater (Mersea Quarters, St. Peters Flats, Colne Point,
Nass End Buoy, St. Osyth), G.M.M., 1963.
Ectocarpus crouanii Thur. Harwich and Dovercourt, Batters (1894).
Ectocarpus erectus Kutz. Clacton, Batters (1894); Blackwater
Estuary (Cocum Hills), G.M.M., 1963.
Giffordia granulosa (Sm.) Hamel. Harwich and Dovercourt, Batters
(1894) (as Ectocarpus granulosus); Blackwater Estuary (St. Peters
Flats, Nass End Buoy, Stoney Point, Bradwell Creek), G.M.M., 1963.
Giffordia mitchellae (Harv.) Hamel River Blackwater (Bench Head
Buoy—Cocum Hills), G.M.M., 1963.
Pilayella littoralis (L.) Kjellm. Walton, Harwich, Dovercourt,
Clacton and Felixstowe, Batters (1894); River Blackwater, Clacton,
Fingringhoe Wick, G.M.M., 1963.
Spongonema tormentosum (Huds.) Kutz. Harwich and Walton
Creek, Batters (1894).
Ralfsiaceae
Ralfsia clavata (Harv.) Crouan. Estuaries of the Orwell and Stour,
Batters (1894).
Ralfsia verrucosa (Aresch.) J. Ag. Felixstowe, Southend, Batters
(1894).
Myrionemataceae
Myrionema strangulans (Grev.) Clacton, Batters (1894).
Elachistiaceae
Elachistia fucicola (Vell.) Aresch. Maldon, Clacton, Batters (1894).
Leptonematella fasciculata (Reinke) Silvae. Harwich, River Black-
water, G.M.M., 1963-64.