CURRENT LITERATURE.

BOOK REVIEWS.

The origin of species and varieties by mutation.

PROFESSOR DEVRIES1 has hit upon a method for presenting his experiments and theories to the English-reading public that is as happy as it is unique. It is commonly the fate of an epoch-making work, such as Die Mutationstheorie has proved itself to be, to undergo a translation into other tongues in the course of three or four years, without alteration except for some inevitable changes for the worse. DeVries has taken into his own hands the preparation of the English exposition of mutation, and we have as a result a book that is written for a very different audience, couched in different language, and prepared in the light of the experiments and discussions of the past four years. The investigator who desires the minutiae of DEVRIES' experimental results will still have recourse for the most part to the earlier volumes, but as investigators are supposed to be conversant with the German language and with the technical terminology there employed, no difficulty results. The investigator, however, will require the present volume for the broader viewpoint, and for the contributions that have appeared since 1901. The great and undisputed field for the present volume is the presentation of mutation to the large and important audience of intelligent people to whom German is a foreign language, and technical terminology more

So.

The volume under consideration is based on a course of lectures given at the University of California in the summer of 1904, and was edited by D. T. MACDOUGAL of the New York Botanical Garden, whose experiments and contributions have done so much to make Americans conversant with the work of DEVRIES. One of the most valuable and interesting of his lectures is the preliminary one, dealing with theories of evolution and methods of investigation. Here there is an excellent portrayal of the relation that exists between his contributions and those of others; and it is at once clear that the work of DARWIN is not opposed but supplemented and strengthened; DARWIN'S comparative studies resulted in the accumulation of a vast array of material, while DEVRIES' work has systematized this material, and has given us an experimental basis for the belief in evolution. It is to be hoped that the perusal of this volume will put an end to the notion, so widely circulated in the newspapers, that DEVRIES is a destroyer of Darwinism.

1 DeVries, Hugo, Species and varieties; their origin by mutation. Edited by D. T. MACDOUGAL. 8vo., pp. xviii+847. Chicago: The Open Court Publishing Co. 1905.

The following lectures outline the characteristics of elementary species, both in nature and in cultivation, and it is shown that natural selection must play a large part in determining their survival. Varieties are shown to differ from elementary species in not possessing anything that is really new, and in originating commonly by the loss of some quality. Several chapters deal with the various kinds of varieties, retrograde, progressive, and ever-sporting; in the same connection the subject of atavism is elucidated, as well as latent characters, and vicinism or variation under the influence of pollination by neighboring individuals. The lectures on mutations deal not alone with Oenothera, but as well with the peloric toadflax, double flowers, and a great many wild and cultivated plants that are supposed to illustrate mutation. A lecture that will be read with great interest by paleontologists, as well as others, is the one that considers the periodicity of mutations, and the relation that mutation bears to the length of geological time. The final lectures present the topic of fluctuating variations, and perhaps it is here that Darwinians will find least comfort in the work of DEVRIES. The closing words of the book, quoted from ARTHUR HARRIS, will be recognized as most apt: "Natural selection may explain the survival of the fittest, but it cannot explain the arrival of the fittest."

In a review of Die Mutationstheorie (BOT. GAZ. 33:236-239. 1902), it was felt to be too soon to express an opinion concerning the place which that work would occupy in the literature of evolution, although it was the reviewer's intuition that this place would be very high. Of the permanent value of that work, and of the work here under review, there is now no doubt at all. "The greatest contribution since DARWIN" is the universal testimony, and there is a feeling on all sides that the answers to many evolutionary questions are close at hand, and that through the application of experiment. To many of us the new volume brings more than did the old, because we have now seen the author face to face, and have perpetually in mind the modest, lovable man, as well as the renowned investigator.-H. C. COWLES.

MINOR NOTICES.

EMERSON has published the results of experiments in the control of the rust and scab of apples. He finds that the rust of apples due to species of Gymnosporangium can be prevented by spraying with Bordeaux mixture if the first application is made when the gelatinous spore-containing projections first appear on the "cedar apples." This spraying should then be followed by a second spraying about ten days or two weeks after the first. He recommends also that the cedar apples be removed from cedar trees near orchards in the winter or early spring, and that where practicable cedar trees themselves should not be allowed to remain within one mile of apple orchards. The scab he found could be prevented by spraying twice with Bordeaux mixture, once just before the apple blossoms open and again just after the blossoms fall.-E. MEAD WILCOX.

2 EMERSON, R. A., Apple scab and cedar rust. Bull. Nebraska Exp. Sta. 88: pp. 21. figs. 9. 1905.

CHRISTENSEN 3 has begun the publication of an Index Filicum, which is intended to do for ferns what the Index Kewensis does for seed-plants. The book will contain a systematic enumeration of the based upon genera, ENGLER and PRANTL's Pflanzenfamilien; an alphabetical enumeration of species and synonyms, which will include all names and combinations of names published from 1753 to 1905 and also names of garden ferns; and an alphabetical catalogue of literature containing critical notes and descriptions of new genera and species. The work will be complete in eleven or twelve parts, and the entire manuscript is ready for printing, awaiting only a sufficient subscription. The first fascicle, just issued, begins the alphabetical list of genera and species, closing with Aspidium.-J. M. C.

MERRILL 4 has attacked the species described in BLANCO's monumental Flora de Filipinas, recognizing that they must be identified and made available so far as possible. He has brought together these identifications in a conveniently arranged bulletin, calling special attention to the species that are yet to be identified. To give some idea of the results attained by this absolutely isolated worker, it may be said that in the two editions of the Flora (1837 and 1845) BLANCO described 1127 species and varieties; about 623 of these were proposed as new, and 504 identified with species of other authors, 219 of them correctly and 285 incorrectly. A large proportion of the new species remain unknown, and only 90 are known to be valid.-J. M. C.

HITCHCOCK 5 has published an elaborately illustrated synopsis of the North American species of Agrostis, recognizing twenty-seven species and describing. three as new. It is announced as the intention of the department to publish occasional monographs of the larger genera of grasses.-J. M. C.

HUSNOT has published the first part of an illustrated synopsis of the Cyperaceae of France, Switzerland, and Belgium. This part contains Elyna, Kobresia, and Carex. The important characters of each one of the 123 species of Carex are illustrated.-J. M. C.

3 CHRISTENSEN, CARL, Index Filicium sive enumeratio omnium generum specierumque Filicum et Hydropteridum ab anno 1753 ad annum 1905 descriptorum adjectis synonymis principalibus, area geographica, etc. Fasciculus 1. pp. 64. Copenhagen: H. Hagerups Boghandel. 1905. Each part 35 6d.

4 MERRILL, ELMER D., A review of the identifications of the species described in Blanco's Flora de Filipinas. Bull. 27, Bureau of Gov't. Labs., Department of Interior. Manila. 1905.

5 HITCHCOCK, A. S., North American species of Agrostis. Bulletin 68, Bureau of Plant Industry, Department of Agriculture. pp. 68. pls. 37. 1905.

6 HUSNOT, T., Cypéracées: descriptions et figures des Cypéracées de France, Suisse et Belgique. Part 1. pp. 48. pls. 12. Cahan, par Athis (Orne): the author. 1905. 5 fr..

NOTES FOR STUDENTS.

APOGAMY in the genus Alchemilla has been investigated very thoroughly by STRASBURGER. The work was suggested by MURBECK'S researches; and his statements that the embryo of the EUALCHEMILLAE develops from the egg without fertilization, and that there is no reduction of chromosomes in the life history, are confirmed. On the other hand, STRASBURGER reaches a different conclusion as to the origin of the embryo sac of apogamous species of Alchemilla, and has a different theory as to the nature of the embryogeny of these species.

More than forty species were studied. In the European species the pollen, except in a few species, is abnormal, the development being checked at various stages. The pollen mother-cells may disorganize or a tetrad may be formed, but the pollen grains fail to be liberated from the mother-cell. In some cases, the division into tube nucleus and generative nucleus takes place, but such pollen grains disorganize early. There are thirty-two bivalent chromosomes in the pollen mother-cells, and sixty-four univalent chromosomes in the vegetative tissues. In American and African species, an examination of herbarium material showed normal pollen, and it is probable that fertilization occurs in the usual way.

In the ovules of apogamous EUALCHEMILLAE one or more megaspore mothercells appear. The nucleus passes through the prophases of the heterotypic division up to the synapsis stage, but here the mode of development changes and the nucleus divides by a typical vegetative division. Division in the embryo sac shows the sporophytic number of chromosomes, so that when the egg is formed it contains the vegetative number of chromosomes. When such an egg develops an embryo without fertilization, STRASBURGER regards the phenomenon not as parthenogenesis but as apogamy. Strictly speaking, it would not be even a case of apogamy, but we should have merely an adventitious embryo like one coming from cells of the nucellus. There is not the beginning of a new generation.

The subniveal EUALCHEMILLAE which form normal pollen show a reduction of chromosomes in the formation of the megaspores, and fertilization takes place in the usual way. Those EUALCHEMILLAE which have not lost their sexuality are chalazogams, and some of them form hybrids.

It seems probable that the extraordinary mutation of the EUALCHEMILLAE has weakened the sexuality, and that the failure of fertilization has brought on the apogamous condition.

Rubus and Rosa, which were also examined, have retained their sexuality in spite of extensive polymorphism. The reduction division and fertilization occur regularly.

Dioecism has in many cases given an impulse toward apogamous reproduction, since the separation of male and female individuals decreases the frequency of fertilization.-C. J. CHAMBERLAIN.

7 Strasburger, E., Die Apogamie der Eualchemillen und allgemeine Geschichtspunkte, die sich aus ihr ergeben. Jahrb. Wiss. Bot. 41:88-164. pls. 1–4. 1905.

ITEMS OF TAXONOMIC INTEREST are as follows: S. LEM. MOORE (Jour. Botany 43:137-150. pl. 471. 1905), in describing numerous new Australasian species, has described a new genus (Cratystylis) of Compositae (Inuloideae), with 3 species, and one (Nepenthandra) of Euphorbiaceae (Crotoneae).—H. CHRIST (Bull. Soc. Bot. France IV. 5:1-69. 1905) has published an account of the Chinese ferns in the collections of the Museum of Natural History, Paris, describing 41 new species and a new genus (Neocheiropteris), to replace Cheiropteris, preempted by a genus of fossil plants.-M. A. Howe (Bull. Torr. Bot. Club 32:241–252. pls. 11-15. 1905) has described new species of Chlorophyceae from Florida and the Bahamas in Halimeda and Siphonocladus, and has established a new genus (Petrosiphon) related to the latter.-H. D. HOUSE (idem 253-260. pls. 16-18), in presenting Viola in New Jersey, recognizes 33 species and describes one as new.- MRS. E. G. BRITTON (idem 261–268) has proposed Pseudocryphaea and Dendroalsia as new genera of mosses, and has described new species in Erpodium.-A. ENGLER (Bot. Jahrb. 36:213-252. 1905) has described the following new African genera: Spondianthus and Nothospondias (Anacardiaceae), Magnistipula (Rosaceae), Pretreothamnus (Pedaliaceae), and Cycniopsis (Scrophulariaceae).-M. L. FERNALD (Rhodora 7:81-92. 1905) has begun the publication of a revision of the North American species of Eriophorum.-J. CARDOT (Rev. Bryol. 32:45-47. 1905) has published two new genera of acrocarpous antarctic mosses, naming them Pseudodistichium and Skottsbergia, the peristome of the latter being described as most extraordinary.-A. A. EATON (Fern Bulletin 13:51-53. 1905) has described a new species and variety of Iosetes from Washington.-J. W. BLANKINSHIP (Montana Agric. Coll. Sci. Studies 1:35-109. pls. 1-6. 1905), in his "Supplement to the flora of Montana," has published new species in Sagittaria, Zygadenus, Salix, Arabis, Physaria, Sedum, Ribes, Saxifraga, Astragalus (2), Lupinus (4), Impatiens, Ammania, Bupleurum, Carum, and Petasites.-JESSIE MILLIKEN (Univ. Calif. Pub. Botany 2:1-71. pls. 1-11. 1904), in a well-illustrated revision of Californian Polemoniaceae, recognizes 6 species of Polemonium, 5 of Collomia, 22 of Navarretia, 36 of Gilia, 31 of Linanthus, and 9 of Phlox, and describes new species in Gilia and Linanthus.-J. M. C.

PEIRCES has studied the dissemination and germination of the seeds of Arceuthobium occidentale on the Monterey pine (Pinus radiata) of California. The structure and mechanics of the exploding fruit are described in detail; and the seeds were observed in the laboratory to be thrown fifteen feet, sticking to whatever they struck. The so-called seeds, by the way, are seeds enclosed in the inner part of the ovary. The field observations indicate that the majority of seeds strike the leaves of the pine, either of the tree on which they grow or of one near by. In germination the root is negatively phototropic and not very sensitive to contact. When growth is blocked by some obstacle the root forms a thick foot-like holdfast, into which the material in the upper end of the embryo

8 PEIRCE, GEORGE J., The dissemination and germination of Arceuthobium occidentale Eng. Ann. Botany 19:99-113. pls. 3-4. 1905.