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NOTES ON ALIEN AND CASUAL PLANTS IN
THE NEIGHBOURHOOD OF WALTHAMSTOW
AND WOODFORD, ESSEX.
By C. NICHOLSON
[Read 29th October 1910].
A REMARK to the effect that I was interesting myself in the
''Alien'' plants of Essex is responsible for my reading the fol-
lowing local notes on a subject in which comparatively little seems
to have been published in a convenient form. We have, of
course, that excellent classic, Gibson's Flora of Essex, in which
the question of alien and casual plants is hinted at more or
less broadly by its shrewd author, but I believe I am right in
saying that no list of such plants recorded for the county has
been compiled. It seems to me, therefore, desirable that the
Club should take the matter in hand, and publish such a list
in its journal which would not only direct fresh attention
to the subject, but also serve as a working list for students,
fresh records and notes being published from time to time. I
may say that, as I have a fair amount of material in hand for
such a list, I should be glad to put it at the disposal of the
compiler. But, in the meantime, I shall be pleased to receive
notes of any unusual plants which have been found, or may
yet be found, in any part of Essex, particularly the S.E. Lists
of such plants from any district will be especially welcome.
All records should include, as far as possible, name of plant,
locality, date when found, whether common or only a single
specimen, and any other notes thought to be of value.
In sending me an interesting list, Mr. Shenstone asks the
very pertinent questions, "What is a casual?" "When does
a stray plant from a garden begin to be a casual?" and "When
does it cease to be a casual and become an established plant?"
This matter of definition of terms is very important, but there
seems to be a good deal of uncertainty, or difference of opinion,
on the subject, and I shall therefore quote the definitions given
by H. C. Watson in his Cybele Britannica, which seem to be
the most generally accepted. They are as follows :
Native. Apparently an aboriginal British species, there
being little or no reason for supposing it to have been introduced
by human agency. O