33
TQ(51)57 598,790 18 South Stifford, Warren Farm Chalk Quarry, forming dense mats
in water bodies in the southern half of the pit. Bracts and
bracteoles short, as in var. vulgaris but spine cells very
abundant and crowded, to twice diameter of the axis in length,
long tapering, pointed and spreading. Plants collected in
early July by Tim Pyner, had the spines arising from the cortex
ridges, and had black oospores. Material collected on 26 July
1999 (KJA), also had black oospores, and the same long,
crowded, spreading non-deciduous spine cells, but they arose
only from the sunken cortex rows. Both forms come within the
variety hispidula, as defined by Moore et al. 1986. [see note
below for detailed discussion]. Pickled material Southend
Central Museum STD.
Chara globularis var. globularis
TL(52)51 569,137 19 White Roding, Farm Reservoir, August 1998. Shirley &
Charles
Watson.
TL(52)52 528,200 19 Gt Hallingbury, Beggar's Hall fishing lake, with Chara vulgaris
var. vulgaris. August 1998. Shirley & Charles Watson.
Note: As predicted in the interim account (Adams, 1997) we have now detected forms of Chara
vulgaris that show transitions on the same plants between var. vulgaris, var. papillata and var.
longibracteata, confirming that these are 'ecomorphs' rather than true varieties with different
genomes. The material from the Warren Farm chalk quarry has the long, straight, spreading, non-
deciduous spine cells of 'hispidula', together with black oospores, which are said to separate C.
contraria from the C. vulgaris agg., (Groves & Bullock-Webster, 1920), and by inference, its var.
hispidula. What we need to establish now, is whether black oospores are genetically tied to long,
straight, pointed, spreading spine cells, or whether these can be found in combination with the blunt
parallel-sided, downward curving spine cells, and variable length bracteoles, of members of the C.
vulgaris agg., winch are supposed always to have brown (ripe) oospores. As pointed out in Moore
et al, 1986 the relative dominance of the primary and secondary cortical rows is variable in forms
with straight, spreading spine cells. Material assignable to C contraria s.s. is supposed to have
poorly developed spine cells arising from the ridges, plus black oospores. Without any other
reliable characters to go on, C. contraria then becomes an artificial construct. A further character
given by Allen, 1950 is that in the sensu stricto C vulgaris agg., the two circlets of stipuloids are
more or less equal in size and blunt, whereas in C. contraria, those in the upper circlet are supposed
to be larger than the lower and more pointed than in C. vulgaris. He used this as an empirical
separator for dried herbarium material. In our material, if anything, those in the lower circlet of
stipuloides were larger, so this character does not seem to be linked either. What we need to do
now, is look at oospores in the other C. vulgaris varieties, and see if they ever have black oospores.
The long straight, spreading spine cell character is so rare, that we are unlikely to be able to
clinch it the other way round by finding it in combination with brown oospores.
References
ALLEN, G.O., 1950. British Stoneworts. Haslemere Natural History Society.
GROVES, J. & BULLOCK-WEBSTER, G.R., 1971. The British Charophyta. Vol.I & II. The Ray Society.
London. 1920 & 1924. Johnson Reprint Corporation.
MOORE, J.A., TEBBS, M. AND GREEN, D., 1986. Charophytes of Great Britain and Ireland. BSBI
Handbook No: 5. Botanical Society of the British Isles.
Bryophytes
Essex Naturalist (New Series) 16 (1999)