The Essex Naturalist 137
TQ(51)59 58,99 18 Doddinghurst, (as N. opaca), near Brentwood, old
pond near Doddinghurst Farm, with C. vulgaris and
C. globularis (as C. fragilis), Sept. 1894.
Coll: hy William Allen, specimen checked Arthur
Bennett. Essex Naturalist. 10, p.190. 1897-98.
TQ(51)69 61 ,90? 18 Spring near Childerditch, July 1890. Coll: W. Hind,
det: Charles C. Babington. W.Hind. As Chara flexilis,
Trinity CollegeDublin Herbarium (TCD). Flora of
Essex, p.405. 1862.
638,952 18 Hutton, (as N. opaca), abundant in the Stud Pond,
10 Aug. 1960. Coll: Stanley T.Jermyn, det:? Eric
Saunders. Flora of Essex, p.45. 1974. Also Natural
History Museum Herbarium (BM). Atlas Specimen
No.1781.
TL(52)70 and ??????? 18/19 Chelmer and Blackwater Canal, between Maldon
TL(52)80 and Chelmsford, 8 August 1891. Dr. Pearl. Essex
Naturalist. 5. p.252. 1891.
TL(52)71 748,125 19 Boreham, old gravel pit nr. Brent Hall, scarce in deep
water amongst plentiful Chara vulgaris and
Potamogeton berchtoldii, sterile. 14 July 1990. Tim
Pyner.
TL(52)81 ??????? 19 Kelvedon, (as N. opaca), pond, 3 June 1878. Henry
Groves. Two specimens in Natural History Museum
Herbarium (BM). Atlas Specimen No. 1782
TL(52)90 973,016 18 Plentiful, deep water, main pond, Asheldham gravel
pits, apices acute, annular incrustations present,
sterile. 11 Oct 1987. Coll: & det: Tim Pyner. Pickled
material in Southend Central Museum Herbarium
(STD).
TM(62)12 154,215 19 Weeley, scattered plants in deep shade, west side of
pond surrounded by trees, beside Weeley Church.
The only macrophyte present Ceratophyllum
demersum. Immature antheridia only, and apices
typically blunt, (i.e. 'N. opaca'). 26 May 1986.(No
oogonia when plants grown on) Coll: & det:
K.J.Adams.
17 Nitella translucens (Persoon) Agardh
This, the largest of our British Nitella species, has such giant (to 2mm diameter) axial
cells that it has heen prodded with microelectrodes and used to measure membrane
potentials in different salt solutions, the vacuole contents being squeezed out and
assayed by flame photometry for sodium, potassium and chloride ions, to try and