THE ALGAL FLORA OF THE RIVER LEE
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Chlorogonium tetragamum Bohlin (S., 1962)
This was seen several times in the Lee plankton and was
grown and observed in mixed cultures. The only previous British
record is from Anglesey (Woodhead and Tweed, 1954).
Lobomonas rostrata Hazen (B. & S., 1961)
Appeared in the Lee during the summer of 1959. It seems to
be quite common, but has probably been overlooked on account
of its small size. No previous British records.
Lobomonas ampla var. okensis Korshikov (B. & S., 1961)
Occurred in cultures of river plankton from Dobb's Weir in
the autumn of 1959. It has not previously been recorded from
this country.
Pteromonas angulosa (Carter) Lemmermann (S., 1962)
Frequent in the plankton as scattered individuals. Numerous
British records.
Pteromonas varians Jane (S., 1962)
This was described by Jane (1944) from a pond in Hertford-
shire. It has been observed on several occasions in the Lee.
Gonium pectorale Mull. Rare.
Gonium sodale (Duj.) Warming.
Much commoner than the previous species, occurring in small
numbers throughout the year.
Pandorina morum (Mull.) Bory
Occurred sporadically in the river plankton, but always in
small numbers, except in the stagnant section at Waltham Lock,
where it was common during the summer months.
Eudorina elegans Ehr. Occasional.
Chlorococcales
Ankyra judayi (G. M. Smith) Fott (S., 1962)
Frequent during the summer months. Cells were isolated and
the life cycle was followed in culture. No undoubted previous
record for this country could be found, though Flint (1950) noted
a similar organism (as Characium ancora) in the plankton of one
of the Thames Valley reservoirs.
Pediastrum duplex Meyen Occasional.
Pediastrum boryanum (Turp.) Meyen
Frequent. This is the commonest species of Pediastrum in
the Lee plankton, and has also been found in mud samples.
Pediastrum tetras (Ehr.) Ralfs Occasional.