20
eventually give way to a tall vigorous sward of grass and cow-parsley
that has to be cut repeatedly at further expense to the tax payer. If the
next section of verge can be left with the natural boulder clay at the
surface it will give rise to a short, easily managed, natural sward with-
out having to be sown, and at the sarae time provide an ideal seed-bed for
the Hare's-ear, all at a fraction of ths cost of top-soiling and seeding.
2 THE RED DATA BOOK OF VASCULAR PLANTS. 2nd edition. 1983
Before going on to the list of Essex plants in the national Red Data Book,
special mention must be made of two undoubtedly native Essex plants that
have not only been missed out, but in my opinion ought really to be among
the 62 given special protection. These are the Hartwort (Tordylium maximum),
now struggling to survive against the council's mowers on Benfleet Downs,
its only extant location in the British Isles, and the Hairy Vetchling
(Lathyrus hirsutus), which fortunately is more plentiful in the same
vicinity. It is interesting that neither of these plants occurs in the
Atlas of the British Flora either. It is to be hoped that they will be
included either in the third edition of the Red Data Book, or preferably
a supplement to the second, - before they become extinct.
Of the other plants listed in the Red Data Book that occur in Essex, apart
from the three given special protection, several are native, but others
are obviously not, though they have been with us for a long time. In alpha-
betical order they are: Campanula rapunculus, Cynodon dactylon, Festuca
longifolia, Galium spurium, Iris versicolor, Ludwigia palustris,
Peucedanum officinale, Rorippa austriaca, and Tetragonobolus maritimus.
The Campanula was formerly grown as a salad plant and is obviously a long
established escape, similarly, Festuca longifolia, although possibly native
on the Breck, occurs in Essex as an introduction in a few places on dry soils.
E.F.C. members may remember being shown it on the North-Outfall Sewer this
summer! Galium spurium is a famous Essex plant that still survives
precariously in the Saffron Walden area, although undoubtedly an introd-
uction of long ago, and Iris versicolor still persists where it was
deliberately introduced in Epping Forest. Ludwigia palustris, the Hampshire
Purslane, which mysteriously appeared in an Epping Forest pond in 1976,
probably got there by natural means, but it is unlikely to be seen again
until this pond dries up again in an equally hot dry summer. A thriving
colony grew quite happily in a damp pool in my garden under a sheet of
polythene, to protect it against the frost, until the winter of 1981/2,
overwintering as swollen pieces of stem. A colony has also been established
at the Cambridge Botanic Garden, the plants clearly belonging to a different
genetic stock from those of the New Forest.
The Hog's Fennel (Peucedanum officinale), although a red data book plant
because it occurs in less than 15 of the 10 x 10 km squares of the
national grid, the criterion for inclusion, is nevertheless quite abundant
in several of its north-east Essex sites, and seems if anything to be on
the increase. There was some doubt about inclusion of the alien Rorippa
austriaca in the 2nd edition of the Red Data Book. Had our two Essex
localities been included, duly sent in on pink cards! - it would probably
have exceeded the 15 square threshold. Ths colony on the west bank of the
Roding at Buckhurst Hill, first discovered in 1967 is still thriving, and
a second colony occurs at the edge of a public open space at Pyrles Lane,
Loughton. Tetraqonobolus maritimus, still occurs on Mersea Island, where
it is known as ths 'Mersea Pea', but its hold is rather tenuous. It runs
riot over the rockery of the house at the end of Empress Avenue, and still
survives in a nearby grassy field, but it seems only a matter of time before
this becomes a housing estate. The small colony at Hockley is also extant,
and similarly does not appear to be increasing. Bermuda-grass (Cynodon) is