210
THE ESSEX NATURALIST
Book Review
The Changing Flora of Britain, edited by J. E. Lousley, The Botanical
Society of the British Isles, 6th July, 1953. 15s. 203 and 6 plates.
Sooner or later every botanist, professional or amateur, meets a question
to which it is difficult to find an answer. The question, in brief, is: "What
is a native plant?" As with so many similar questions, the answer cannot
be given in a word or a sentence. Since the end of the last Ice Age, which
may have denuded this country of most of its flora, a steady flow of plants
has been entering the land by various means. Birds, animals, winds and
the works of Man have been responsible for these introductions, and with
the recent speeding-up of the tempo of life and the vast increase in the
imports of supplies chiefly food, the number of such introductions has in-
creased rapidly. In addition, the incidence of two world wars, with the
movements of men and supplies, has added not a little to the list of plants
observed in Britain. Some survive for a short time but find climatic or
other conditions unsuitable and die out. Others not only survive but succeed
in establishing themselves, either in a limited way, or finding conditions
to their liking, spread and soon form part of the British Flora, Unless
these introductions, establishment and subsequent spread are fully and
carefully recorded by the botanists of the time, it becomes impossible to
decide whether or not a plant is "native".
The Botanical Society of the British Isles, at their Conference in 1952,
discussed this subject in all its aspects, and the results are here set forth
to attempt to answer this question. In Our Changing Flora the effects of
introductions by natural causes, by human actions, the influence of our
varied soil and climate on the plants here established, the relationships
between our British plants and those of adjacent continental countries, are
all considered and discussed in detail. Fascinating accounts of the plants
to be found after the treatment of land with shoddy show that Australian
and African plants are making themselves at home in our countryside and
some perennials have succeeded in establishing themselves and may even
become in time a feature of our flora. The introduction of plants by gar-
deners, nurserymen and cattle-breeders has its eventual effect on our flora.
In the Isles of Scilly a species of Buttercup, Ranunculus muricatus Linn,
introduced with bulbs, has become so thoroughly established in the bulb
fields there as to become a pest. A similar introduction in Essex in the
17th century, the Ivy-leaved Toadflax, Cymbalaria muralis Bailing., which
is reputed to have been first grown in Coy's famous garden at Ockendon,
has now spread throughout the greater part of the British Isles, and forms
a charming addition to our flora.
The effects of primitive cultivations by our early ancestors, the intensive
grazing of the downs by the flocks when Britain produced wool for the world
as well as for her own use, the introduction of railways and modern means
of transport, including the airways, changes in our styles of feeding and
clothing, have all contributed to make this study one of more than absorbing
interest. This report presents the position in admirable form which is
worthy of study, not only by our botanists, but by all who take an intelligent
and reasonable interest in current affairs.
B.T.W.