THE ALGAL FLORA OF THE RIVER LEE
197
Crucigenia tetrapedia (Kirchn.) W. & G. S. West Rare.
Tetrastrum Stourogeniaeforme (Schroder) Lemm. Occasional.
Kirchneriella lunaris (Kirchn.) Mobius Rare.
Selenastrum gracile Reinsch Rare.
Dictyospliaerium pulchellum Wood Frequent.
Botryococcus braunii Kutz. Rare.
Ankistrodesmus braunii (Nag.) Brunnth. Rare.
Ankistrodesmus acicularis (A. Br.) Korshikov Rare.
Ankistrodesmus arcuatus Korshikov Occasional.
Ankistrodesmus falcatus var. spirilliformis G. S. West Occasional.
Ankistrodesmus curvulus Belcher & Swale (1962b) Occasional.
Raphidonema longiseta Vischer
This species is an important constituent of the plankton in
early spring, reaching 500 cells per ml. in April and May 1958. It
does not seem to have been recorded for this country previously,
possibly due to confusion with Ankistrodesmus acicularis, though
it is extremely common. Cells from the Lee varied from 68 to 135u
in length.
Coelastrum microporum Nag.
This is frequent in the plankton, often occurring as single
cells. In August 1958 and 1959 it reached 200 colonies per ml. in
isolated collections.
References
Belcher, J. H. & Swale, E. M. F. (1961). Some new and uncommon
British Volvocales. Brit. phycol Bull., 2 : 56-62.
Belcher, J. H. & Swale, E. M. F. (1962). Some Chlorococcales new to
Britain. Brit. phycol. Bull, 2: 121-125.
Belcher, J. H. & Swale, E. M. F. (1962b). Culture studies on Ankis-
trodesmus and some similar genera. Brit, phycol. Bull., 2: 126-
132.
Belcher, J. H. & Swale, E. M. F. (1963). Some new and uncommon
British Volvocales. Brit, phycol. Bull., in the press.
Flint, E. A. (1950). An investigation of the distribution in time and
space of the algae of a British water reservoir. Hydrobiologia,
2: 217-240.
Jane, F. W. (1938). Some Hertfordshire flagellates, 2. Trans. Herts, nat.
Hist. Soc, 20: 340-351.
Jane, F. W. (1944). Studies on the British Volvocales, 1. Two new
Volvocalean flagellates. New Phytol, 43: 36-43.
Lund, J. W. G. (1937). Contributions to our knowledge of British Algae,
6. J. Bot., Lond.: 305-314.
Scourfield, D. J. (1944). The nannoplankton of bomb-crater pools in
Epping Forest. Essex Nat., 27: 231-241.
Swale, E. M. F. (1959). Some uncommon Chlorophyceae from the
River Lee. Brit. phycol. Bull, 1 (7): 71-72.
Swale, E. M. F. (1962). Studies in the phytoplankton of a calcareous
river. Ph.D. thesis, University of London.