Epigraph
Producer’s note:
Species and Varieties Their Origin by Mutation
Lectures delivered at the University of California
By
Hugo DeVries
Professor of Botany in the University of Amsterdam
Edited by
Daniel Trembly MacDougal
Director Department of Botanical Research
Carnegie Institution of Washington
THE ORIGIN OF SPECIES
The origin of species is a natural phenomenon.
LAMARCK
The origin of species is an object of inquiry.
DARWIN
The origin of species is an object of experimental investigation.
DeVRIES.
PREFACE BY THE AUTHOR
The purpose of these lectures is to point out the means and methods by which the origin of species and varieties may become an object for experimental inquiry, in the interest of agricultural and horticultural practice as well as in that of general biologic science. Comparative studies have contributed all the evidence hitherto adduced for the support of the Darwinian theory of descent and given us some general ideas about the main lines of the pedigree of the vegetable kingdom, but the way in which one species originates from another has not been adequately explained. The current belief assumes that species are slowly changed into new types. In contradiction to this conception the theory of mutation assumes that new species and varieties are produced from existing forms by sudden leaps. The parent-type itself remains unchanged throughout this process, and may repeatedly give birth to new forms. These may arise simultaneously and in groups or separately at more or less widely distant periods.
The principal features of the theory of mutation have been dealt with at length in my book “Die Mutationstheorie” (Vol. I., 1901, Vol. II., 1903. Leipsic, Veit & Co.), in which I have endeavored to present as completely as possible the detailed evidence obtained from trustworthy historical records, and from my own experimental researches, upon which the theory is based.
The University of California invited me to deliver a series of lectures on this subject, at Berkeley, during the [vii] summer of 1904, and these lectures are offered in this form to a public now thoroughly interested in the progress of modern ideas on evolution. Some of my experiments and pedigree-cultures are described here in a manner similar to that used in the “Mutationstheorie,” but partly abridged and partly elaborated, in order to give a clear conception of their extent and scope. New experiments and observations have been added, and a wider choice of the material afforded by the more recent current literature has been made in the interest of a clear representation of the leading ideas, leaving the exact and detailed proofs thereof to the students of the larger book.
Scientific demonstration is often long and encumbered with difficult points of minor importance. In these lectures I have tried to devote attention to the more important phases of the subject and have avoided the details of lesser interest to the general reader.
Considerable care has been bestowed upon the indication of the lacunae in our knowledge of the subject and the methods by which they may be filled. Many interesting observations bearing upon the little known parts of the subject may be made with limited facilities, either in the garden or upon the wild flora. Accuracy and perseverance, and a warm love for Nature’s children are here the chief requirements in such investigations.
In his admirable treatise on Evolution and Adaptation (New York, Macmillan & Co., 1903), Thomas Hunt Morgan has dealt in a critical manner with many of the speculations upon problems subsidiary to the theory of descent, in so convincing and complete a manner, that I think myself justified in neglecting these questions here. His book gives an accurate survey of them all, and is easily understood by the general reader.
In concluding I have to offer my thanks to Dr. D.T. MacDougal and Miss A.M. Vail of the New York Botanical Garden for their painstaking work in the preparation of the manuscript for the press. Dr. MacDougal, by [viii] his publications, has introduced my results to his American colleagues, and moreover by his cultures of the mutative species of the great evening-primrose has contributed additional proof of the validity of my views, which will go far to obviate the difficulties, which are still in the way of a more universal acceptation of the theory of mutation. My work claims to be in full accord with the principles laid down by Darwin, and to give a thorough and sharp analysis of some of the ideas of variability, inheritance, selection, and mutation, which were necessarily vague at his time. It is only just to state, that Darwin established so broad a basis for scientific research upon these subjects, that after half a century many problems of major interest remain to be taken up. The work now demanding our attention is manifestly that of the experimental observation and control of the origin of species. The principal object of these lectures is to secure a more general appreciation of this kind of work.
HUGO DE VRIES.
Amsterdam, October, 1904.
[ix]
PREFACE BY THE EDITOR
PROFESSOR DE VRIES has rendered an additional service to all naturalists by the preparation of the lectures on mutation published in the present volume. A perusal of the lectures will show that the subject matter of “Die Mutationstheorie” has been presented in a somewhat condensed form, and that the time which has elapsed since the original was prepared has given opportunity for the acquisition of additional facts, and a re-examination of some of the more important conclusions with the result that a notable gain has been made in the treatment of some complicated problems.
It is hoped that the appearance of this English version of the theory of mutation will do much to stimulate investigation of the various phases of the subject. This volume, however, is by no means intended to replace, as a work of reference, the larger book with its detailed recital of facts and its comprehensive records, but it may prove a substitute for the use of the general reader.
The revision of the lectures has been a task attended with no little pleasure, especially since it has given the editor the opportunity for an advance consideration of some of the more recent results, thus materially facilitating investigations which have been in progress at the New York Botanical Garden for some time. So far as the ground has been covered the researches in question corroborate the conclusions of de Vries in all important particulars. The preparation of the manuscript for the printer has consisted chiefly in the adaptation of oral [xii] discussions and demonstrations to a form suitable for permanent record, together with certain other alterations which have been duly submitted to the author. The original phraseology has been preserved as far as possible. The editor wishes to acknowledge material assistance in this work from Miss A.M. Vail, Librarian of the New York Botanical Garden.
D.T. MacDougal.
New York Botanical Garden, October, 1904.
PREFACE TO THE SECOND EDITION.
THE constantly increasing interest in all phases of evolution has made necessary the preparation of a second edition of this book within a few months after the first appeared. The opportunity has been used to eliminate typographical errors, and to make alterations in the form of a few sentences for the sake of clearness and smoothness. The subject matter remains practically unchanged. An explanatory note has been added on page 575 in order to avoid confusion as to the identity of some of the plants which figure prominently in the experimental investigations in Amsterdam and New York.
The portrait which forms the frontispiece is a reproduction of a photograph taken by Professor F.E. Lloyd and Dr. W.A. Cannon during the visit of Professor de Vries at the Desert Botanical Laboratory of the Carnegie Institution, at Tucson, Arizona, in June, 1904.
D. T. MACDOUGAL.
December 15, 1905.
Seed varieties of pure, not hybrid origin. Differences from elementary species. Latent characters. Ray-florets of composites. [xiii] Progressive red varieties. Apparent losses. Xanthium canadense. Correlative variability. Laciniate leaves and petals. Compound characters.
VI. Stability and real atavism. 154
Constancy of retrograde varieties. Atavism in Ribes sanguineum Albidum, in conifers, in Iris pallida. Seedlings of Acacia. Reversion by buds.
VII. Ordinary or false atavism.
Vicinism or variation under the influence of pollination by neighboring individuals. Vicinism in nurseries. Purifying new and old varieties. A case of running out of corn in Germany.
VIII. Latent characters. 216
Leaves of seedlings, adventitious buds, systematic latency and retrogressive evolution. Degressive evolution. Latency of specific and varietal characters in wheat-ear carnation, in the green dahlias, in white campanulas and others. Systematic latency of flower colors.
IX. Crossing of species and varieties. 247
Balanced and unbalanced, or species and variety crosses. Constant hybrids of Oenothera muricata and O. biennis. Aegilops, Medicago, brambles and other instances.
X. Mendel’s law of balanced crosses. 276
Pairs of antagonistic characters, one active and one latent. Papaver somniferum. [xiv] Mephisto Danebrog. Mendel’s laws. Unit-characters.
D. EVERSPORTING VARIETIES.
XI. Striped flowers. 309
Antirrhinum majus luteum rubro-striatum with pedigree. Striped flowers, fruits and radishes. Double stocks.
XII. “Five leaved” clover.
Origin of this variety. Periodicity of the anomaly. Pedigree-cultures. Ascidia.
XIII. Polycephalic poppies. 369
Permanency and high variability. Sensitive period of the anomaly. Dependency on external conditions.
XIV. Monstrosities.
Inheritance of monstrosities. Half races and middle races. Hereditary value of atavists. Twisted stems and fasciations. Middle races of tricotyls and syncotyls. Selection by the hereditary percentage among the offspring.
XV. Double adaptations.
Analogy between double adaptations and anomalous middle races. Polygonum amphibium. Alpine plants. Othonna crassifolia. Leaves in sunshine and shadow. Giants and dwarfs. Figs and ivy. Leaves of seedlings.
E. MUTATIONS.
XVI. Origin of the peloric toad-flax. 459
Sudden and frequent origin in the wild state. Origin in the experiment-garden. Law of repeated mutations. Probable origin of other pelories.
XVII. The production of double flowers. 488
Sudden appearance of double flowers in horticulture. Historical evidence. Experimental origin of Chrysanthemum segetum plenum. Dependency upon nourishment. Petalody of stamens.
XVIII New species of Oenothera. 516
Mutations of Oenothera lamarckiana in the wild state near Hilversum. New varieties of O. laevifolia, O. brevistylis, and O. nanella. New elementary species, O. gigas, O. rubrinervis, albida, and oblonga. O. lata, a pistillate form. Inconstancy of O. scintillans.
XIX. Experimental pedigree-cultures. 547
Pedigree of the mutative products of Oenothera lamarckiana in the Botanical Garden at Amsterdam. Laws of mutability. Sudden and repeated leaps from an unchanging main strain. Constancy of the new forms. Mutations in all directions.
XX. Origin of wild species and varieties. 576
Problems to solve. Capsella heegeri. Oenothera biennis cruciata. Epilobium hirsutum cruciatum. Hibiscus Moscheutos. Purple beech. Monophyllous strawberries. Chances of success with new mutations.
XXI. Mutations in horticulture. 604
Chelidonium majus lacinatum. Dwarf and spineless varieties. Laciniate leaves. Monophyllous and broom-like varieties. [xvi] Purple leaves. Celosia. Italian poplar. Cactus dahlia. Mutative origin of Dahlia fistulosa, and Geranium praetense in the experiment-garden.
XXII. Systematic atavism.
Reappearance of ancestral characters. Primula acaulis umbellata. Bracts of crucifers. Zea Mays cryptosperma. Equisetum, Dipsacus sylvestris torsus. Tomatoes.
XXIII. Taxonomic anomalies. 658
Specific characters occurring in other cases as casual anomalies. Papaver bracteatum monopetalum. Desmodium gyrans and monophyllous varieties. Peltate leaves and ascidia. Flowers on leaves. Leaves. Hordeum trifurcatum.
XXIV. Hypothesis of periodical mutations. 686
Discovering mutable strains. Periods of mutability and constancy. Periods of mutations. Genealogical trees. Limited life-time of the organic kingdom.
F. FLUCTUATIONS.
XXV. General laws of fluctuations.
Fluctuating variability. Quetelet’s law. Individual and partial fluctuations. Linear variability. Influence of nutrition. Periodicity curves.
XXVI. Asexual multiplication of extremes. 742
Selection between species and intra-specific selection. Excluding individual [xvii] embryonic variability. Sugar-canes. Flowering cannas. Double lilacs. Other instances. Burbank’s method of selection.
XXVII. Inconstancy of improved races
Larger variability in the case of propagation by seed, progression and regression after a single selection, and after repeated selections. Selection experiments with corn. Advantages and effect of repeated selection.
XXVIII. Artificial and natural selection. 798
Conclusions. Specific and intra-specific selection. Natural selection in the field. Acclimatization. Improvement-selection of sugar-beets by various methods. Rye. Hereditary percentage and centgener power as marks by which intraspecific selection may be guided.
Index_________________________________________827
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A. INTRODUCTION