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In two papers, published in I922, Turesson (I922a, b) introduced the ecotype concept and its importance in the study of the constitution and origin of species was almost immediately recognized. Ecologists and taxonomists alike appreciate the value of combined field observations and controlled cultural experiments. There was some criticism, in part justified, that the field studies of populations and of the conditions of their environment were insufficiently extensive and intensive and that the ecotype concept was based too much on selected individuals and not on the study of whole populations or of sufficiently large random samples of such. Nevertheless, Turesson's researches have opened up new lines of research and full recognition of his great contributions to the study of species problems must be gratefully accorded by anyone familiar with the facts. There is no intention, or need, to give details of the early investigations on ecotypes. A very useful summary is given by Barton-Wright (I932). More recently, Gregor (I944) has published a most valuable summary of much recent research and trends of thought in this subject. The present paper is concerned mainly with two matters: the full significance of changes in definition of terms first used by Turesson in I922, and the relation between genecology and taxonomy. Gregor (1944) touched on both these problems which were also referred to by the writer in an earlier paper (Turrill, I938) and more recently in a review (Turrill, I942). An investigator is unavoidably impressed more by his own experiences, by the examples with which he himself has worked, and by the difficulties he meets, than by those of others, and the value of concepts, terms, definitions, and schemes of classification can only be tested pragmatically. Genecologists have often criticized taxonomists, sometimes not without reason, but sometimes from a misconception of the taxonomist's functions. Taxonomists have too often ignored these criticisms and indeed the whole experimental work of genecologists, though there is increasing improvement in this respect. The present writer again expresses his appreciation of both the methods used and the results obtained in genecological research and is confident that any criticisms he makes will be accepted in the constructive spirit in which they are offered.

1. Forty-eight hybrid families involvingSaxifraga granulata andS. rosacea have been made under fully controlled conditions and the results of their analysis are given in this paper.

In the New Phytologist, 30, 284 (I93I), we published a short paper on flower mutations in the common primrose, Primula vulgaris Huds. (P. acaulis L.). About the same time as the experiments recorded in that paper a small amount of research was done in colour factors in British material of the primrose. 'The results have some interest since they in part confirm and in part extend earlier work. Primroses proved difficult to cultivate at Potterne under controlled conditions. 'rhis and the pressure of other research prevented the experiments being carried further.

"Natural selection or the preservation of favoured races in the struggle for life" is an explanation primarily of adaptation and only secondarily of the origin of species. It rests on the assumption that the differences between individual members of a species which live together in the same district are heritable, and that they may determine the life or death of the individuals in question at an earlier or later time than one another. In other words, that definite variation in structure or in function may be responsible for a selective death-rate. It is evident that this selective death-rate will only be recognizable statistically, and that a heavy non-selective infantile death-rate, such as that which occurs generally in marine teleosts, merely reduces the population within which selection of adults may operate. The existence of such a selective mortality is fundamental to the theory, and various authors, from the time of Weldon, have tried to establish its occurrence in definite cases, always without any significant result. It is presumably true that relatively gross abnormalities lead to early death, but in some cases (e.g., Rhynchonella) the average size of asymmetrical shells seems, on a mere inspection, to be no smaller than that of normal individuals from the same horizon and locality. It would thus be valuable to have any new evidence on this point, or indeed any suggestion of cases which might be capable of investigation. The nature of the variations which do occur in nature and which may provide the raw material of evolution, requires experimental investigation. The varieties recognized by systematists, are, I think rightly, held by them to include two types: those which occur within a single population, and which therefore cannot be accounted for by environmental effects (except for those special cases involving microclimates), and those which are assumed to be related to local variations in the environment, and are hence of a geographical significance. * In some special cases, e.g., the spring and summer broods of moths, the varieties are clearly the result of climatic changes, but in most, e.g.

1. It is shown thatAnthyllis Vulneraria L. is a very polymorphic species, especially in habit and flower colour. The studies deal almost entirely with wild British material.

Professor Seward, in his introductory remarks, referred to the publication in 1899 of Mr. Clement Reid’s “Origin of the British Flora,” and spoke of the more recent researches of Mrs. Reid which have considerably extended our knowledge of British Tertiary floras. He drew attention to the striking contrast between the early Tertiary floras and the present plant population of Britain, and to the changes exhibited by successive floras in geographical relationship and in composition. He emphasized the importance of reconstructing the geological background as well as the botanical features of the series of floras preceding and subsequent to the Glacial period. Reference was made to the more controversial question of the effect of the Ice Age upon the plant-world, and he expressed the hope that the discussion would enable botanists to form a more definite opinion on the crucial problem of survival or extinction of flowering plants when the British area was exposed to the maximum invasion of ice. Professor Seward offered a hearty welcome to Dr. du Reitz of Uppsala, whose work on Scandinavian floras provided particularly important data having a direct bearing upon the history of the Pre-Glacial and Post-Glacial floras of Britain.

Summary An attempt is made, within a limited space, to indicate the importance of taxonomy, especially of the Spermatophyta, to the more recently developed branches of biology, and to show that these in turn are reacting on taxonomy. Certain basic logical problems are discussed and a via media between extreme lines of development is suggested. The interactions between taxonomy and cytology, genetics, ecology, palaeontology, phylogeny, biometrics, and physiology are discussed briefly with a few selected examples. Practical suggestions for improving taxonomic methods and for increasing co-operation between different branches of biology are made in various places throughout the text. Lastly, proposals are made that in practice should lead gradually and some way towards an “omega” or perfected taxonomy, which, idealistically, should be a completed classification of all biological knowledge.

1. Comparative descriptions are given of British material ofSaxifraga rosacea, S, caespitosa, andS. hypnoides. 2. Families have been raised from selfings and from crossings of our stock plants of these taxa, and from reciprocal crosses ofS. hypnoides andS. granulata. 3. In the discussion it is shown that genetical sterility barriers are not important in keeping the taxa distinct and their absence or incompleteness explains the occurrence of ‘intermediates’ in certain wild populations and in some plants in cultivation. 4. The doubtful taxonomic value of the differences betweenS. caespitosa andS. rosacea is considered and the need for further comparative researches, especially on Welsh and Scottish populations, is suggested.

An account is given of a wide range of plants ofRanunculus ficaria collected from a number of English counties. Various stock plants from among these were selfed and crossed together under full control. Analysis of stock plants and families has been for: presence or absence of tubers in the axils of the cauline leaves, leaf shape, leaf margin, mottling of leaf surface, anthocyanin blotch on leaf surface, petal colour, anthocyanin on back of petals, and sex. Many of the plants have been examined cytologically. The characters listed have been shown to have genetic bases, and for some it has been possible to suggest genetic details.

INTRODUCTION Scope of the Paper 247 Derivations and Definitions of Terms .248 HISTORICAL DEVELOPMENT OF PLANT CLASSIFICATION . .252 Pre-Linnaean Systems 252 Linnaeus 256 Post-Linnaean and Pre-Darwinian Systems .256 Darwin .264 Post-Darwinian Systems 266

Grundlagen und Methoden einer Erneuerung der Systematik der hoheren Pflanzen Die Forderung dynamischer Systematik im Bereiche der Blutenpflanzen. Von Dr. Franz Buxbaum. Pp. xi + 224. (Wien: Springer-Verlag, 1951.) 44s. 6d.

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Hooker visited Syria and Palestine in the autumn of 1860 (see L. Huxley, Life and Letters of Sir J. D. Hooker 1: 528–34, 1918). No full account of the expedition was prepared, so far as the present writer has been able to ascertain, but a number of articles of phytogeographical interest were published. In the Natural History Review 2: 11–8 (1862) there is one under the title “On the cedars of Lebanon, Taurus, Algeria, and India.” In this, Hooker describes the grove of Cedrus libani in the Kadisha valley at 6000 feet (1829 m). The cedars grew on a moraine immediately bordering a stream and nowhere else. They formed “one group, about 400 yards in diameter, with an outstanding tree, or two, not far from the rest, and appear as a black speck in the great area of the corry and its moraines, which contain no other arboreous vegetation, nor any shrubs, but a few small barberry and rose bushes, that form no feature in the landscape” (pp. 12–3). The trees numbered about 400 and were disposed in nine groups. Though of various sizes there was no tree of less than 18 inches girth and “no young trees, bushes, nor even seedlings of a second year’s growth” were found. Calculating from annual rings in a branch Hooker estimated “the youngest trees in Lebanon would average 100 years old, the oldest 2500, both estimates no doubt widely far from the mark.” (p. 13). Hooker doubts if cedar forests were ever extensive on the Lebanon though there is no doubt that the grove has, within the historic period, “increased and diminished in extent, owing to secular changes in the climate” (p. 15).

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J. D. Hooker never visited the Arctic region but he worked intensively at many collections made in various parts of the Arctic in the first six decades of the 19th century and now at Kew. The results of his studies are summarized in his paper “Outlines of the Distribution of Arctic Plants”, published in Trans. Linn. Soc. Lond. 23: 251–348 (1862). Apparently Hooker defined the “Arctic” very definitely by the Arctic Circle, at least the map accompanying his paper suggests this as does also the sentence “The arctic flora forms a circumpolar belt of 10° to 14° latitude, north of the arctic circle.” Hooker estimates the flora within the Arctic Circle to consist of 925 Cryptogams and 762 Phanerogams (214 Monocots. and 548 Dicots.).

It may be some comfort to botanists of the post-Hitler period to know that hooker’s paper “On the vegetation of the Galapagos Archipelago, as compared with that of some other tropical islands and of the continent of America”, in Trans. Linn. Soc. Lond. 20: 235–62 (1851) which was read to the Linnean Society on 1 and 15 December 1846, did not appear until five years later! It is based on a preceding paper by Hooker: “An enumeration of the plants of the Galapagos Archipelago; with descriptions of those which are new” read on 4 March, 6 May, and 16 December 1845 and printed in the Trans. Linn. Soc. 20: 163–234 (1851). This latter paper is a systematic list of the specimens collected in the Galapagos Islands by Charles Darwin, James Macrae, and a few other naturalists. Darwin visited the islands during the voyage of H.M. Ship ’Beagle’ and devotes a chapter to them in his “Journal of Researches” (London, ed. 1, 1839; ed. 2, 1852; chapter XVII).

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Mention must be made of the very full essay-review, by J. D. Hooker, of A. De candolle’s Geographie Botanique Raisonnee, published in hooker’s Journ. of Bot. (Kew Journ. Bot.) 8: 54–64, 82–8, 112–21, 151–7, 181–91, 214–9, 248–56 (1856). The importance of this review is twofold. First, it shows how very fully Hooker studied De candolle’s methods and theories, and, though he sometimes disagrees with many of his conclusions, they undoubtedly influenced some of his later work. Secondly, in the final instalment, under the heading “Concluding remarks,” Hooker discusses at some length his view on the nature of species. De Candolle believed “that the majority of species were created such as they now exist,” but Hooker adds “there is not a shadow of a proof of this.” The arguments for transmutation of species are put forward and include: “the fact that species are variable”, that “this theory of transmutation accounts better for the aggregation of Species, Genera, and Natural Orders in geographical areas, and for their limitation”, and that transmutation involves “less of the marvellous at first sight” than does special creation. On the other hand, Hooker says, “unfortunately transmutation brings us no nearer the origin of species, except the doctrine of progressive development be also allowed, and, as we can show, the study of plants affords much positive evidence against progressive development, and none in favour of it” (p. 252).