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A WEEKLY JOURNAL DEVOTED TO THE ADVANCEMENT OF SCIENCE, PUBLISHING THE OFFICIAL NOTICES AND PROCEEDINGS OF THE AMERICAN ASSOCIATION
FOR THE ADVANCEMENT OF SCIENCE.
FRIDAY, JULY 14, 1905.
THE FUNDAMENTAL PROBLEMS OF PRES
EXT DAY PLANT MORPHOLOGY." CONTENTS.
A FEW months ago I was in Jena in The Fundamental Problems of Present-day order to attend the unveiling of the statue Plant Morphology: PROFESSOR K. GOEBEL. 33
there erected to M. Schleiden. Now there Scientific Books:Clements’s Research Methods in Ecology:
is hardly any other place which has been of PROFESSOR CONWAY MACMILLAN. Strutt so much significance in the development of on the Becquerel Rays: G. B. OBEAR...... 45
plant morphology as this small university scientific Journals and Artic'es.
town. It was there that Goethe, the originaSocieties and Academies :
tor of the term ‘morphology,' busied himThe Missouri Society of Teachers of Mathematics: PROFESSOR L. D. AMES. The self with morphological studies, and foundTorrey Botanical Club: EDWARD W. BERRY.
ed the idealistic system which has influenced The University of Colorado Scientific so
ciety: PROFESSOR FRANCIS RAMALEY...... 48 our thought-often unsuspectedly- till the Special Articles :
present day. There Schleiden, in outspoken jero Work on Wheat Rust: PROFESSOR opposition to the conceptions of the idealHESBY L. BOLLEY. Concerning the Identity of the Fungi causing an Anthracnose of
istic morphology, gave new life to the thethe Street-pea and the Bitter-rot of the ory of development founded by Caspar Apple: PROFESSOR JOHN L. SHELDON. Indications of an Entomophilous Habit in
Frederick Wolff in a neighboring hall in the Tertiary Species of Quercus: DR. C. J. middle of the eighteenth century, and so VALBY. Bathygnathus Borealis, Leidy, and the Permian of Prince Edwards Island:
paved the way for the brilliant discoveries PROFESSOR E. C. CASE. A System for of William Hofmeister. And who does not Filing Pamphlets: DR. WITMER STONE.... 50
know what meaning Jena has won as the ('urrent Notes on Meteorology :Barometer and Weather; Monthly Weather
citadel of phylogenetic morphology, first Rerier, Annual Summary : Climate of through the work of Haeckel in zoology Jerusalem ; Marine Meteorological Service
and later through that of Strasburger in of Chile: PROFESSOR R. DEC. Ward...... 54 Jotes on Forestry:
botany? In such a morphological atmosWhy Prairies are Treeless; Principles in phere the question forces itself upon us, in
rolred in Determining Forest Types ...... 55 what relation do the morphological quesThe Fossil Arachnida of Bohemia: H. F. O... 57
tions of the present stand to those of the Ertended Erplorations of the Atmosphere by
past? Are they still unchanged in spite the Blue Hill Observatory ..... .........
of the immense increase of empirical maRegulations governing the Sixth Inter. national Congress of Applied Chemistry..
? Lecture delivered at the Congress of Arts and Arthur Woodberry Edson.................. 61 Science in St. Louis, September 21, 1904, by ProGeorge Homans Eldridge..
62fessor K. Goebel, University of Munich; transKrientific Notes and News.............
62 lated by Professor F. E. Lloyd. The theme was l'nirersity and Educational News......
proposed by the Direction of the Congress. Since the time allowed for the lecture was but forty-five
minutes, the various questions could be indicated for review should be sent to the Editor of SCIENCE, Garri. 200-00-Hudson, N. Y.
MSS. intended for publication and books, etc., intended
terial, and have the methods of their solu- to be contrived a terminology for the distion only changed? Or have the problems tinction and description of single plant themselves become different ?
forms. From this function morphology To reply to this question is not easy, soon, however, became distinct, thus conand the answer must vary with the point stituting an independent discipline which of view of the one who makes it. For on its part had served taxonomy a more morphology is yet far from being an exact important service than one might have at science, the results of which force them- first expected. For while taxonomy, in selves upon us with the compulsion of order to find its way amid the maze of necessity. This is due to the difficulty of plant forms, had to keep in view the differthe materials, a difficulty which compels ential characters and the separation of us to seek for hypotheses and other sub- single forms from each other, morphology jective means of explanation. It thus found itself under the necessity of detercomes about that views not only concerning mining what was common to the most vari. the goal of morphology, but also as to the ous forms and was accordingly directed way in which this goal is to be reached, toward more general questions; morpholare widely diverse, and my own views con- ogy taught, as Goethe expressed it, 'Die cerning the fundamental problems of mor- Glieder der Pflanzen im Zusammenhänge phology are certainly far from being ap- zu betrachten, und so das Ganze in der Anproved by all morphologists.
schauung gewissermassen zu beherrschen.' We may, indeed, say that, apart from It resulted in the knowledge that, when we minor differences, there are in morphology regard plants singly, manifold as their two main trends of thought which, appar parts appear, they may yet be referred to ently at least, are opposed to each other, a few elementary forms, and further, morone of which we may denominate formal, phological research showed that the paraland the other causal. Causal morphology lelism between different plant forms could is that the aim of which is to determine be understood most easily under the asthe causes, in the widest sense, of form sumption which we designate the theory of relations; this kind of morphology is the descent. The establishment of the theory of youngest, and is far less widely diffused descent was the result of the morphological than the formal. To us of a later period research. This we must here especially it may seem like a remarkable pleonasm, emphasize, for it shows what significance to speak of a ‘formal morphology.' Mor
morphology has gained in respect to our phology is, of course, the doctrine of form,
general conception of organisms. But the and therefore any morphology appears to
theory of descent has also reacted upon be, in the nature of the case, a formal one,
morphological research, to such an extent, and as a matter of fact has been in its his
indeed, that it has been held that phylotorical development. But in spite of this
genetic research is to be regarded as the fact this definition is historically justified,
sole business of morphology. Thus, for for it designates the tendency of morphol
example, Scott has said: ogy which regards form as something which stands alone for itself, and takes The object of modern morphological botany is cognizance neither of the functions of or the accurate comparison of plants, both living and
: extinct, with the object of tracing their real relagans nor of how they have arisen. This
tionships with one another, and thus of ultimately formal morphology arose at first out of the
constructing a genealogical tree of the vegetable necessities of taxonomy. There had first kingdom. The problem is thus a purely historical one, and is perfectly distinct from any of the ques. ble each other in the general plan of their organitions with which physiology has to do.
zation. This resemblance is often expressed by This position is certainly justified from
the term “unity of type '; or by saying that the
several parts and organs in the different species the standpoint of the paleontologist. For
of the class are homologous. The whole subject him, for whom nothing but dead material is included under the general term of Morphology. is at hand, there remains nothing else to do This is one of the most interesting departments of than to make known, through careful com natural history, and may almost be said to be its parative study, the structure and relation- very soul. ships of those organisms whose remains are The significance of formal morphology available. This is a very important busi- can not be more forcibly expressed than it ness. The beautiful results of phytopale was by Darwin. And yet we see that, in ontological research, such as have been at Germany at least, interest in morphological tained during the last decade in England problems has greatly decreased. Morphoand France, have very materially furthered logical treatises have become relatively less our knowledge of plant forms, and have numerous; morphological books, even such made to live again before our eyes in a excellent ones as, e. g., Eichler’s ‘Blüthenmost surprising manner and in the finest diagramme,' do not pass through a second details of their structure, types long since edition, while anatomical and physiological vanished from the surface of the earth. works appear repeatedly in new editions ;
But does this limitation of morphology evidently meeting the demands of the boto the comparative phylogenetic method tanical public more fully than morphologwhich is imposed upon the paleontologist ical works. This may be referred to exist also for the morphological study of reasons which lie partly without and partly living plants ?
within morphology itself; both turn out to There are many of the opinion of Scott; be true. Histology, cytology and experiand, indeed, a special ‘phylogenetic meth- mental physiology have developed remarkod,' which is said to be a characteristic of ably; new methods in this field promise modern morphology, has even been talked new results; particular lines of work, howof.
ever, such as descriptive anatomy, are espeWere this the case, then the only differ- cially favored because the perfection of the ence between the morphology of the present methods of research have quite materially and the earlier, idealistic morphology lightened the task of working through a would consist in this, that in the place of vast array of materials, especially for those the general ideas with which this operates, to whom the other fields of botanical study as, e. g., 'type,''plan of organization,' etc., are more or less unfamiliar. there would be found phylogenetic con. But the reasons for the phenomenon ceptions. Such general abstractions are, which lie within the field of morphology however, even now difficult to escape, since are also clear. Some parts of morphology we can set forth real descent-series only in are well worked out, as, e. g., the doctrine the fewest instances, and, accordingly, we of the more obvious form relations of can not actually point out the stem forms. plants, and the homologies, at least in the Yet Darwin himself said:
large, are determined, although in the matWe have seen that the members of the same ter of detail much remains vague and offers class, independently of their habits of life, resem a wide field for exhaustive studies in devel
* Address to the botanical section, British Asso- opment. More and more, however, these ciation for the Advancement of Science, Liver. pool, 1896.
36 Origin of Species,' 2: 142.
studies bear the stamp of repetition and remained the same: the most comprehencomplement, from which the stimulus of sive comparison not only of mature forms, newness is wanting, or they are carried on but also their development. A special upon materials which are very difficult to ‘phylogenetic method’ there is not, but only obtain. The constructions of the idealistic a phylogenetic conception of morphological morphology, however, often proved to be problems. These are, however, just as at untenable.
first was the case with idealistic morpholBut the first experiments towards a ogy, purely formal. Modern morphology, causal morphology, brought disillusion. in my sense, however, differs from the For only a short time lived the hope of older in this, that it goes beyond the method being able to answer, e. g., the question as of mere comparison. It allows the setting to the arrangement of leaves through the up of genetic trees to rest for the while, effect of mechanical factors, or, to refer the since, with our present knowledge, this form-relations of a plant to the direct in- meets with insuperable difficulties and has fluences of gravity and light on the plant. brought almost as much disappointment as It soon became evident, however, that such the idealistic morphology. For just this involved problems are not to be unraveled reason, namely, because we are persuaded by such simple means, and this may well that no other forces have been at work durhave resulted in the suppression of interesting the phylogenetic history than those in morphology.
which now control the development of each At this point phylogenetic morphology particular organism, do we wish, first of appeared to take on a new lease of life. all, more exactly to learn what these are. This, however, in natural science is con- We are concerned not alone with the denected, on the one hand, with the appear- termination of the single successive stages ance of a new, creative (?) idea, and, on of development. These must, of course, be the other hand, with the discovery of new followed, but in addition we should follow methods. Now the theory of descent has all phenomena which may be got at by our powerfully stimulated morphological re- means of observation, whether directly, by search. But has it brought to it, as, e. g., the microscope, or by chemical analysis. Strasburger has held, a new method, the We may, therefore, say: The basal probphylogenetic? Alexander Braun has al- lem of the present day morphology is not ready properly answered this question in phylogenetic development, but development the negative.
in general. We must, therefore, take our Scott, also, has maintained that historical departure from the investigation of indimorphology (as regards both living and vidual development (of ontogeny), for fossil plants) is dependent upon compara- only this lies before us complete and withtive study, that is, makes use of the same out any break, and further, because the method as was in evidence before the ap- study of ontogeny only may proceed from pearance of the theory of descent; indeed, the experimental point of view. An unthe most important homologies in the plant derstanding of development is possible only kingdom became known through Hofmeis- when the conclusions, to which the observater at a time when the idea of descent was tion of the phenomena of development has far from that general acceptation which it led us, rest upon experimental proof; in at first gained through the life work of other words, when we ask questions of Darwin.
Nature, and obtain our answers to them. The method has then from first to last Every little step-and with such only are we now concerned-beyond the mere foliose, because the vegetative body of the descriptive consideration of development is former is much more simple in construchere of significance, and brings the possi- tion than that of the latter, and between bility of further progress. And small in- them there are found gentle gradations, deed, I may add, appears to be such ad Recently, however, the attempt has been vance to those who, from the beginnings of made to derive the thallose from the foliphylogenetic morphology have, like Sisy- ose forms. This is not the place to examine phus, sustained their courage to roll again the evidence for or against such derivation. and again up the mountain the rock of How vacillating is the point of view from phylogeny as often as it has rolled down. which it is judged what form is primitive
It may now be attempted to examine is shown by the various positions which somewhat more closely in certain particular have from time to time been given to the examples the relation between phylogenetic apetalous dicotyledons. and causal morphology. One of the The old morphology regarded these as changes which phylogenetic morphology reduced forms because their flowers are has brought with it is that it seeks to ascer- less fully differentiated than those of most tain which form is 'primitive' and which of the other dicotyledons. Eichler has, derived. Idealistic morphology has borne however, already shown that there is no in upon us no conviction on this ques- ground for maintaining that the corolla in tion, since it derives all forms from a type the . 'Iulifloræ' and 'Centrospermæ' has which is present only as a conception. suffered reduction; and on this point we But phylogenetic morphology must, on the can only agree with him. But must they, one hand, always reckon with the possi- because the perianth shows simpler form bility of polyphyletic development, and, on relations and also because the number relathe other hand, it can operate not only with tions within the flower are not always conreversionary structures, as did the ideal stant, be therefore primitive ? Even if we istic morphology, but must be far more admit that these groups have a great geoconcerned in determining which forms logical age, it is not proved that they stand within the series which it proposes stand as regards their total organization on a nearest the common point of derivation. Tower plane of development; old and primiIt seeks then with diligence after 'primi- tive forms are the same only when it can be tive forms. But in this search we meet shown that the former stand nearer to the with great difficulties. In the first place, stem forms of the angiosperms than other We are inclined to regard those forms as forms. If this is not capable of proof, primitive which have simple form-rela- then the old forms may just as well be the tions, and unmarked division of labor. end terms of long developmental series as But such forms may also have arisen by others, only that the differentiation of reversion, and if one looks over botanical organs has not taken place to the same literature, he sees, at least so far as the degree as in the others. Now, we do not relationships between the larger groups are know the stem forms if the angiosperms, concerned, there exists no agreement as and they may never, perhaps, be known. to which forms are to be regarded as primi. But even if we content ourselves by recontive and which derived; often opinion on structing them on the basis of comparative this point changes with the fashion. Thus study, I can find no reason, e. g., to regard the thallose liverworts have up till now the Cupuliferæ as primitive forms, while been regarded as more primitive than the I can find many reasons for not doing so.