To produce a new Flora of Cambridgeshire is to be responsible for accepting a great tradition and adding to what may well claim to be the most famous sequence of local taxonomic records in the world. When the present volume was planned it was hoped to publish it in the tercentenary year of John Ray's Catalogus Plantarum circa Cantabrigiam nascentium published in 1660 and marking not only its author's entry into the study of natural history but the first scientific treatment of our native plants. Ray's book records a large number of species new to botany and gives first lists of plants found in particular types of localities, the lanes of Chesterton and Ditton, the chalk of the Gog Magogs and Cherry Hinton, the woods of Madingley and Kingston, Newmarket Heath and the Devil's Dyke and the fens at Teversham and Stretham ferry. How thoroughly he observed is witnessed by the fact that several species are still only found in the place where he discovered them, and one, Veronica spicata, which he recorded as ‘in a close near the beacon on the left hand of the way from Cambridge to Newmarket in great plenty’, was lost from his day till after much research Dr W. H. Mills rediscovered it in the thirties.

Since Ray's time the Cambridgeshire plants have been resurveyed by Charles Cardale Babington, Professor of Botany in 1860–a careful and accurate record giving for the first time lists of some of the ‘difficult’ genera–a worthy successor to the Catalogus;, and by A. H. Evans, a keen field-naturalist who brought the records up to date in 1939.

John Ray published the first Flora of Cambridgeshire just over three hundred years ago, and since then the study of our local plants has been almost continuous. Relhan (1785) and Babington (1860) published further Floras at approximately hundred-year intervals, and this Flora was first planned by the Cambridge Natural History Society to appear in 1960, the tercentenary of Ray's work. Unfortunately we underestimated the amount of work involved, and regretfully decided to abandon the original date.

This work, based upon the Natural History Society's records, departs from the standard practice of most local Floras in that it does not give long lists of localities under each species. In their place is a concise list of Ordnance Survey Grid References which give an adequate picture of the main features of distribution of the species. The space saved allowed us to include taxonomic notes, comments and keys, which we believe will prove to be more valuable than the traditional distribution data.

1519 species are listed, of which 27 are Pteridophyta, 3 Gymnospermae, 1228 Angiospermae and 261 Bryophyta. Of the 1231 seed plants, 968 are native (65 of these being extinct), 19 are doubtfully native, 81 are naturalized, 31 are planted trees, and 195 casuals, garden escapes or relics of cultivation. Of the 27 Pteridophyta one is introduced and nine extinct. Of the Bryophyta 222 are mosses (20 extinct) and 39 liverworts (4 extinct).

HISTORY OF THE STUDY OF THE FLORA

For three hundred years Cambridgeshire has been one of the best known counties, botanically, in the British Isles. The first list of plants made in the county was by Samuel Corbyn (1656), although a few records date from the sixteenth and early seventeenth centuries, made by men like Turner and How, who were beginning to study the flora of the country as a whole. However, the first work of real importance was that of the illustrious John Ray (cf. Raven, 1942), who in 1660 published a 12mo volume of 182 pages entitled Catalogus Plantarum circa Cantabrigiam nascentium. This has long been celebrated as the first comprehensive local British Flora. It was the result of nine years' work, and consists of an alphabetical list of plants found in the Cambridge area. It gives localities of plants, which in several cases can still be found there today, for example, Geranium sanguineum, ‘Found on Newmarket heath in the Devils ditch, also in a wood adjoining to the highway betwixt Stitchworth (Stetchworth) and Chidley (Cheveley)’.

In 1663 Ray published a 13-page appendix to the Cambridge Catalogue, and after this in 1685 appeared a second appendix consisting of 30 pages, edited by Peter Dent, a Cambridge apothecary. There was no second edition of the Cambridge Catalogue, but in 1670 Ray published his Catalogus Plantarum Angliae (ed. 2, 1677), in which all plants occurring in Cambridgeshire were marked with the letter C.

Introduction

In the eight years since M. C. F. Proctor's paper, ‘A Bryophyte Flora of Cambridgeshire’ (Proctor, 1956) went to press, knowledge of the bryophytes of the county has been considerably extended. About 30 additions have been made to the county list, and the frequency and distribution within the county of many species is now better known. For several species, the first record for the county has been put back over 50 years, by the finding of Cambridgeshire specimens in F. Y. Brocas's collection at Saffron Walden Museum, and through the correction of faulty identifications of specimens in the Cambridge University Herbarium. A few published records have been omitted when there is doubt about the identity of the plants. A start has been made with the recording of bryophytes within 10 km. squares of the National Grid, and this has led to collecting in new areas, with some unexpected finds. Details of the habitat, locality, collector and date for these records have been deposited in the library of the Botany School. I am particularly indebted to Mr P. J. Bourne, who has made numerous excursions to all parts of the county in search of bryophytes. His collecting has led to over 600 additions to the 10 km. square lists. Others who have helped are acknowledged on p. xiii.

With few exceptions the system and nomenclature in the following account follows that of J. E. Dandy (1958) for the Vascular Plants, P. W. Richards and E. C. Wallace (1950) for the Mosses, and E. W. Jones (1958) for the Liverworts. Following the scientific name, a well-known vernacular one may be given. If there is a well-known name for a number of species all in one genus (e.g. Willow-herb for Epilobium species) it is placed in parentheses after the generic name. Following the specific vernacular name is the first known record for the plant in the county. This may be based on either a published record, a field record or a herbarium specimen. On the next line follows a list of synonyms that are used by Babington (1860), Evans (1939) or Clapham, Tutin & Warburg (1952). Old binomials and pre-Linnaean names by the earlier authors are given in Babington (1860). An account of the habitat of the species is then given with any notes on rare, difficult or interesting species.

The distribution is indicated by listing the Ordnance Survey Grid Reference numbers given on the Map. Note that most of the 10 km. squares are in 100 km. square 52; but a few squares in the north of the county belong to 100 km. square 53, and these are given at the end of the main (52) series. Numbers in square brackets are given in a separate series.