Plant Science Bulletin archive
Issue: 1970 v16 No 4 Winter
PLANT SCIENCE BULLETIN
A Publication of the Botanical Society of America, Inc.
VOLUME 16 DECEMBER, 1970 NUMBER 4
Chipping Away at Early Land Plants: Of People, Places, and Perturbations
H. P. Banks Cornell University1
My original intent was to devote this lecture to teaching. But I found my thoughts to be too direct, too simple, and too few to make a convincing report. So I shall have to be satisfied by a few specific remarks about teaching and then go on to a consideration of some research problems.
Firstly, too many seem to have forgotten that a teacher is a man. This man, to be a good teacher, needs love for his subject and enthusiasm in its presentation. Real enthusiasm needs freedom from inhibitions and demands that he "give out." Far too many otherwise excellent presentations miss the mark because the teacher is too serious about it all. The world won't end if our courses are dropped, but our students will be turned off by ponderous phrases and pompous presentations, even just overly serious presentations. The good teacher understands human nature, understands people—students are people. The good teacher does two things simultaneously. While he is exploring and exploiting his material with students, he is simultaneously analyzing their reactions. This latter guiles the course of the former during every class meeting whatever its locale.
Secondly, don't bother to ask if plants are relevant. Instead make their relevance obvious by directing questions at the material and eliciting answers. Questioning and thinking are relevant to any man's life or career. The asking and answering of questions is what research is all about and it's what education should be all about.
Finally, is a liberal education still needed in our Society? I say emphatically yes as far as the teaching profession goes, and I'll even suggest that without it the intellectual value of our subject will be lost.
Now to fall back on the subject closest to my heart. But I shall approach it from the standpoint of past and present persons who have influenced me, thus paying a well-deserved tribute to the importance of teaching, teachers, and students.
1Address of the Retiring President of the Botanical Society of America, presented at the Society's annual banquet, August 26. 1970, at Bloomington, Indiana.
As an undergraduate at Dartmouth I was introduced to the joys of primitive land plants and their role in the phylogeny of vascular plants by the enthusiastic presentation of Rhynia and Horneophyton by Carl L. Wilson. As you know he is senior author of the superb textbook Botany---Wilson and Loomis.
The attraction of these early land plants is the myriad of questions they raise: where are the fossils to be foundwhy—whence did they evolve—exactly when—in how many forms—how rapidly did speciation occur—what can we learn of their habitat—in what associations did they occur—are the fossils identical wherever found in the world—what can we learn of the paleogeography and paleoecology of Devonian time—how many whole plants can we reconstruct—how precisely can we pinpoint the time at which distinguishable subdivisions of vascular plants were evolved—what can we learn of the exact time of origin of major characteristics of vascular plants—what do Devonian plants contribute to phylogeny—what was happening in the animal world at the same time—to say nothing of the technical problems they pose for anyone who wants to learn their secrets.
Also at Dartmouth William Patten was teaching a freshman course entitled "Evolution." Patten devoted his research to a strenuous search for a "missing link" between invertebrate and vertebrate animals. His zealously pursued thesis was that a group of primitive armored fishes, the ostracoderms, filled the bill. But what caught my imagination were his exciting accounts of trips to Spitsbergen, Gaspe, and other localities whence he returned with an abundance of material. Among his collections from the Gaspe Peninsula were beautiful "fronds" belonging to a supposed Devonian fern Archaeopteris. The sequel is obvious. My first collecting of Devonian plants was done on the Gaspe Peninsula and included Archaeopteris.
Subsequently at Cornell I came under the influence of the master of teaching, research, and writing, the late Arthur J. Eames. Eames, at the time, was completing his Morphology of Vascular Plants: The Lower Groups and was erecting the subdivision of vascular plants Psilopsida for the Rhynia-type of Devonian fossil and the living PsilotaIes. Equally stimulating was the enthusiasm of the late Loren C. Petry who reveled in the joys of a problem needing solution. Petry had collected on the Gaspe Peninsula in the early thirties. Among his finds were calcitic nodules containing plants with preserved cell structure. I was lucky to get more of these and obviously began peeI-ing the nodules in an attempt to reconstruct a plant. In
the midst of this first project I got waylaid by a travelling salesman, a shoe salesman, from southeastern New York. As you may be aware, good salesmen are often extremely alert men always on the watch for something new. This particular one was attending a nut tree growers' meeting and stopped by to tell us about some fossil nuts being turned up by a retired engineer during road-building operations through Devonian strata. The "nuts" proved to be small masses of pyritized wood. But the engineer, Mr. William Deats, led me to a dense deposit of a lycopod that became Colpodexylorz deatsii in my reconstituted thesis.
Now to go back a little in time. Why was Petry interested in Devonian plants? The answer is a stimulating note by George R. Wieland of fossil "cycad" fame. Wieland wrote in Science in 1922, one year after publication of the last in a series of superb papers by Kidston and Lang. Their description of the intimate anatomical details of the plants of the Rhynie chert beds in Scotland had fired the imagination of many botanists who cared about the phylogeny of vascular plants. Wieland remarked on the vast expanse of Devonian rocks stretched across the North American continent. He noted the large number of invertebrate and vertebrate fossils they contained and the use of these fossils in establishing the chronological sequence of Devonian strata. But he wondered about the paucity of reports of plants from these beds. He stressed the dependence of good phylogeny on the closest attention to the chronological appearance of the plants in the fossil record. He asked leading questions such as: is there a petrified Psilophyton2—is there a petrifaction flora in North America .comparable to the Rhynie chert?—are there any seeds in Devonian rocks? Answers to most of Wieland's questions, and others, will be apparent as we go along.
Petry's first response to Wieland was to investigate a marine limestone layer of early Upper Devonian age in central New York. In this he found Callixylon, Sphenoxylon, and other less-well-known genera.
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Subsequently, Chester Arnold produced an extensive monograph on Callixylon as his doctoral dissertation under Petry, and Dale Thomas, another student, described the Sphenoxylon in detail.
Clearly the Devonian of North America did contain a petrifaction flora. Even more significant was the gymnospermous anatomy of the fossils, quite in contrast to the simple anatomy of the Rhynie plants, although only a relatively few million years younger than Rhynia.
Now to go back even more in time. Fossil plants were illustrated in the monumental publications of the Geological Survey of New York State. Lardner Vanuxem in 1842 figured what we now call Arch+aeosigillaria vanuxemi.
Nearly one hundred years later Arnold described a lycopod whose stem was covered by spine-like outgrowths, naming it Gilboaphyton. Then Grierson and Banks located specimens displaying the characteristics of both genera. By making transfer preparations we demonstrated that the outer surface of the stem was smooth but bore numerous laminar leaves, not spines. Additionally we found a lobed protostele in the center of the stem. Subsequently we found a specimen showing leaves in adaxial view. They were quite similar to those of some specimens of Selaginella. This and other work on Devonian lycopods has led us to the conclusion that the fossils bore an amazing resemblance to modern species and that club mosses have been a distinctive group of organisms ever since their origin in Lower Devonian (Siegenian) strata.
One year after Vanuxem, James Hall in 1843 figured a specimen of what we now call Archaeopteris balliana. Our first big haul of Archaeopteris came from a lens in a quarry near Durham, in eastern New York, to which an amateur naturalist, Mr. Vernon Haskins, had led me. From this collection Hueber obtained both anatomy and morphology of fertile fronds. Then the construction of yet another reservoir dam, near Cannonsville, east central New York, supplied a vast collection of vegetative and fertile Archaeopteris with anatomy provided by petrifactions. Mr. Raymond Baschnagel of Delhi, New York was a major force in amassing this collection which Carluccio studied. Soon we discovered from anatomy that the "frond" had both branch traces and leaf traces. As a result Carluccio, Hueber, and Banks concluded that the so-called frond was really a branch system bearing leaves. Beck has just read a paper at these meetings extending these results. The fertile "pinnules" proved to be much dissected leaves, bearing sporangia adaxially. Meantime others had been busy. Arnold had demonstrated that Archaeopteris was heterosporous and Beck had found an Archaeopteris "frond" attached to a large axis which he identified as a petrified Callixylon. This produced a plant with gymnospermous anatomy and somewhat fern-like foliage for which he coined the name progymnosperm. He effectively laid to rest the concept of Archaeopteris as a Devonian fern. This work also opened up a whole new area of speculation about the phylogeny of vascular plants.
The profusion with which we find well-preserved mass-es of Archaeopteris in lenses indicates to me that it grew
on the low-lying, terrestrial portion of the Devonian delta that was forming in eastern New York, and that parts of the plants fell into small ponds where they were compressed into the lenses which are now exposed occasion-ally by major earth-moving projects.
Somewhat later than Vanuxem and Hall, and in Lower rather than Upper Devonian strata, Sir James W. Dawson, then Principal of McGill University, embarked in summer 1858 on a momentous trip to the tip of the Gaspe Peninsula. Dawson had learned about Gaspe plants from Sir William E. Logan, founder and first Director of Geological Survey of Canada. Logan had observed fossil plants during mapping expeditions in 1843 and had told Dawson about them. Dawson's first trip, 15 years later, was successful, and within a year a paper appeared in the Quarterly Journal of the Geological Society of London describing a new plant, Psilophyton princeps. Either ships were faster in those days or editors were!
As an aside, perhaps I should point out that Dawson was a good example of the versatility of paleobotanists. As Principal of McGill he was a successful money-raiser and innovator. In the latter direction he not only built science at McGill into a position of leadership, he taught botany, zoology, geology, and chemistry, founded an engineering college, and a college for women.
So in 1859, the same year Darwin's Origin of Species appeared, Dawson published Psilophyton princeps, a slender, dichotomizing, spiny plant with supposed lateral fructifications and rhizome. He considered it a possible relative of living Psilotuns. In 1871 Dawson established a variety, P. princeps var. ornatum, for another Gaspe plant supposed to bear paired terminal sporangia, stout spines, and scalariform tracheids.
The vicissitudes of these two taxa constitute a long and intriguing story, too long for presentation here. Suffice it to say that the various organs of Psilophyton were not found in organic attachment, and as Hueber and I reported in 1967 there were two different genera involved. First is the true P. princeps for which we selected a type specimen. Second was the variety ornatum which has yet to be placed in a new genus. The first had paired terminal - sporangia that split longitudinally during dehiscence and had centrarch primary xylem. Hueber described this plant in greater detail in 1968. The second organism bore lateral sporangia whose dehiscence was distal and was supplied by an exarch xylem srtand.
For the first group I proposed in 1968 the name Trimerophytina, a group I consider advanced in many characters over the simpler Rhynia-type.
For the second type I have suggested the group name Zosterophyllophytina, and my slides illustrative of this type are a selection taken from several members of the group including the ornatum type of Psilophyton and the Crenaticaulis described recently by Davis and me.
And now to dispell the myth that paleobotanists are interested only in anatomy, a statement I've read in Science within the year, let's change the subject to another group of people and set of data.
While the more recent of the above events were going on, stratigraphic paleontologists and geochronologists were actively building a more precise chronology and correlation of Devonian strata (Table 1). I illustrate seven subdivisions of the Devonian Period which spanned some 50 million years, and four subdivisions of Silurian. Both time of commencement and the duration of each are given. Were the time available we could examine as well the numerous lesser units into which each of these has been subdivided. All of this subdividing is easier to do in marine deposits containing an abundance of invertebrates but remarkable strides have been made in correlating with them the contemporaneous fresh-water, or continental; strata in which accumulations of plants are much denser. The point is that we are beginning to get the kind of chronological data Wieland regarded as essential to a good phylogeny. An important ingredient for this project is close cooperation among paleobotanists, stratigraphers, paleontologists, and palynologists. This, in fact, is beginning to take place through the medium of international conferences on boundary problems, e.g., the boundary between Silurian and Devonian Periods. But it demands that all learn to speak one another's jargon!
The increased precision in geochronology has produced many changes, some of which make the paleobotanical data far more sensible than they were before. Two examples are the Baragwenathia flora in Australia and the Rhynie chert flora in Scotland. The former is now regarded as late Lower Devonian rather than Silurian, the latter as late Lower Devonian rather than Middle Devonian. Addition-ally, widespread interest in biogeochemistry, especially of Precambrian strata, Ied to the discovery of algae in these ancient rocks and of apparent eucaryotic green algae in rocks deposited nearly one billion years ago. I refer, of course, to such compounds as amino acids, fatty acids, alkanes, and pristanes isolated from rocks and presumed to be degradation products of organisms and to the studies of such men as Barghoorn and Schopf.
It was this kind of new knowledge that led me to start arranging early vascular plants chronologically.
Two groups, the Rhynia- and Zosterophyllum-types, seem to occur in Late Silurian.
Two groups, the Rhynia- and Zosterophyllum-types, lived in earliest Devonian (Gedinnian) time. By Siegenian there were four major groups, the first two plus lycopods and trimerophytes (Psilophyton), and three lesser groups, the barinophytes, sciadophytes, and fan-leaved types.
In Emsian time three more groups appeared, cladoxylaleans, sphenophyres, and the first of the progymnosperms (Protopteridiunt-like forms).
Thus ten groups of vascular plants evolved during late Silurian and early Devonian time. The time span involved was under 35 million years. There is no need to continue into Middle and Upper Devonian because the number of kinds of vascular plants continues to in-crease in progressively younger strata, a continuation of the trend started earlier.
Next you may ask what is the present status of the earliest demonstrable vascular plant and has any effort been made to summarize the current status of the phylogeny of vascular plants?
Lang in 1937 wrote an outstandingly good and analytical paper on the flora of the Downtonian deposits in
Wales. He described, among other things, a simple vascular plant of the Rhynia type. Both vascular tissue and cutinized, trilete spores found in situ demonstrated conclusively that Cooksonia was a vascular plant. At that time the Downtonian was considered to be a boundary deposit of either Late Silurian or Early Devonian age. It seemed to me to have the oldest vascular plant flora.
In 1962 Obrhel found a similar plant in Czechoslovakia in beds (Pridoli) that were, and still are, held to be upper-most Silurian in age. So Obrhel's plant appeared to be somewhat older. Ishchenko (1969) has reported Cooksonia in the Skala beds in Podolia, and I have a note in press on a Cooksonia from the Bertie formation (Cayugan Series) in New York. As a result of a series of inter-national conferences on the Silurian-Devonian boundary, the appearance of certain invertebrates (especially graptolites, conodonts, and ostracodes) has been designated as the end of Silurian and start of Devonian deposition. This decision makes the four deposits equivalent in age—all Upper Silurian. I mean the Downtonian in Wales, the Pridoli in Czechoslovakia, the Skala in Podolia, and the Cayugan Series (Bertie limestone) in New York. Thus the oldest currently acceptable vascular plant, Cooksonia, is found at three or four widely spaced geographic localities. The time of appearance of this fossil is speculative, but I'll say in round numbers 400 million years ago, five million before the start of Devonian deposition.
Further, there is a report by Petrosian, which I've not seen, of the discovery of a Zosterophyllum in the Skala beds of Podolia. If this proves acceptable, then the two groups
Rhynia-type and Zosterophyllum-type appeared almost simultaneously in the fossil record, that is in the youngest stage of Silurian time.
One hopes that palynologists working with isolated spores in the same strata might lend support to this macrofossil evidence. I am happy to report that in general they do. There is abundant documentation of the appearance of a few spores in Early Silurian time and a steady increase in number of species and in their morphological variation through Devonian time. Homospory comes first, heterospory follows, and, in Late Devonian as Pettitt and Beck have now demonstrated, the first seed appears. There is only one flaw in this story. That is ignorance whether the appearance of an apparent vascular plant spore in late Early Silurian means we must seek actively for macrofossils older than the present Cooksonia, or it means that cutinized spores produced in quartets evolved earlier than other characteristics of vascular plants. Right now this ignorance only emphasizes the tentative nature of our conclusions and that our students will surely depart from our conclusions as new data accumulate.
The second question concerns attempts to put these new data, into a phylogenetic series. So I offer you a tentative chart which makes only a few major points. First, there were some groups that started and ended with no obvious descendants (sciadophytes, barinophytes, fan-shaped leaves). Then there seem to have been two productive groups, the Rhynia-type and the Zosterophyllumtype. This latter I speculate gave rise to both lycopods and giant lepidodendrids. Lycopods have persisted. The Rhynia-type gave rise to trimerophytes represented by Psilophyton, and from these most vascular plants have some-how arisen. There is no time for further detail but this is something at which subsequent workers can shoot.
The future: I think I've already demonstrated how easily current hypotheses can be shown erroneous or, some-times, supported but here are a few ideal examples.
1. Protopteridium is shown in many textbooks as the first plant to bear a fern frond. Bonamo, working with Tetraxylopteris, demonstrated that this is probably a fertile branch system.
2. I was taught not to waste time on Devonian strata in western North America because they were all marine. Dorf first demonstrated the fallacy of this by finding and describing a flora at Beartooth Butte in Wyoming. Now several good deposits are known.
3. Intensive collecting and improved technical ability can add greatly to the precision of our knowledge. Examples:
4. Yes, I visualize the day when we'll know many Devonian plants as plants rather than as isolated organs, when we'll be able to speak intelligently about habitats and associations, when we'll know the length of time that was required to evolve new species, and the algae from which vascular plants did evolve. I think we'll learn whether the origin of vascular tissue was related to the origin of metabolic pathways for the manufacture of lignin (perhaps in the Silurian). I think we'll know much more about the possible role of 02 concentration in the atmos-
phere, its role in the formation of ozone, and their role in shielding Earth's surface from lethal ultra-violet radiation, thus permitting the occupation of dry land. And of course I'll be watching for confirmation of my wildest statement, actually a primitive attempt at precision, that all the phylogenetically important innovations among vascular plants are found during the 50-million-year adaptive radiation of land plants that occurred in the Devonian Period. Ted Delevoryas has picked me up on this one and allowed as how all the evolution after Devonian time was just "frosting on the cake."
In lieu of the illustrations that accompanied this talk, a few citations in which they may be found are given below. In the same list are sources of some of the remarks made in the text.
Arnold, Chester A. 1930. The genus Callixylon from the Upper Devonian of central and western New York. Pap. Michigan Acad. Sci., Arts and Letters 11: 1-50.
. 1937. Observations on fossil plants from the Devonian
. 1939. Observations on fossil plants from the Devonian
Banks, H. P. 1963. The early history of land plants, p. 73-107. In, E. T. Drake, Ed., Evolution and Environment: a symposium presented on the occasion of the 100th anniversary of the foundation of Peabody Museum of Natural History at Yale University. Yale Univ. Press, New Haven.
-. In press. Occurrence of Cooksonia, the oldest vascular land plant macrofossil, in the Upper Silurian of New York State. Indian J. Bot.
, and M. R. Davis. 1969. Crenaticaulis, a new genus of Devonian plants allied to Zosterophyllum, and its bearing on the classification of early land plants. Amer. J. Bot. 56: 436-449.
Beck, C. B. 1960. The identity of Archaeopteris and Callixylon. Brittonia 12: 351-368.
. 1970. Stelar morphology in some progymnosperms.
Bonamo, P. M., and I-I. P. Banks. 1967. Tetraxylopteris schmidtii: Its fertile parts and its relationships within the Aneurophytales. Amer. J. Bot. 54: 755-768.
Carluccio, L. M., F. M. Hucber, and H. P. Banks. 1966. Archaeopteris macilenta, anatomy and morphology of its frond. Amer. J. Bot. 53: 719-730.
Chaloner, W. G. 1967. Spores and Land Plant Evolution. Rev. Palaeobot. and Palynol. 1: 83-93.
Dawson, J. W. 1859. On fossil plants from the Devonian rocks of Canada. Quart. Jour. Geol. Soc. London 15: 477-488.
. 1871. The fossil plants of the Devonian and Upper
Dorf, E. 1933. A new occurrence of the oldest known terrestrial vegetation from Beartooth Butte, Wyo. Bot. Gaz. 95: 240-257.
Grierson, J. D., and H. P. Banks. 1963. Lycopods of the Devonian of New York State. Palaeontographica Amer. 4(31): 219-295.
Hall, J. 1843. Report of the survey of the fourth geological district. Geology of New York, Part 4: 1-525.
Harland, W. B., A. G. Smith, B. Wilcock, Editors. 1964. The Phanerozoic Time-Scale. Quart. J. Geol. Soc. London 120S: 1-458.
Hueber, F. M. 1967. Psilophyton: The genus and the concept. In, D..Oswald, Ed., Int. Symposium on the Devonian System.
Alberta Soc. Petroleum Geologists, Calgary, Canada. Vol. 2: 815-822.
Hueber, P. M., and H. P. Banks. 1967. Psilophyton princeps: the search for organic connection. Taxon. 16: 81-85.
Ischenko, T. A. 1969. The Cooksonian paleoflora in the Skala horizon of Podolia and its stratigraphical significance. Geol. J. 29: 101-109. (in Russian)
Lang, W. H. 1937. On the plant-remains from the Downtonian of England and Wales. Phil. Trans. Roy. Soc. Lon-don 227B: 245-291.
Marten, L. C., and H. P. Banks. 1966. Triloboxylon ashlandicum gen. et sp. nov. from the Upper Devonian of New York. Amer. J. Bot. 53: 1020-1028.
Obrhel, J. 1962. Die Flora der Pfidoli-Schichten (Budnany-Stufe) des mittelbohmischen Silurs. Geologic 11: 83-97.
Petrosian, N. M. 1968. In 3' Internat. Symposium of the Silurian-Devonian boundary and the stratigraphy of the Lower and Middle Devonian. A guide to the geological excursion on Silurian and Lower Devonian deposits of Podolia (Middle Dnestr. River). Ministry of Geol. of U.S.S.R. All-Union Geol. Sci. Research Inst. Leningrad. p. 23.
Pettitt, J. M., and C. B. Beck. 1968. Archaeosperma arnoldiia cupulate seed from the Upper Devonian of North America Contrib. Mus. Paleont. Univ. Michigan 22: 139-154.
Richardson, J. B., and T. R. Lister. 1969. Upper Silurian and Lower Devonian spore assemblages from the Welsh Border-land and South Wales. Palaeontology 12: 201-252.
Scheckler, Stephen E. 1970. Evolutionary trends in primitive
Schopf, J. W. 1968. Microflora of the Bitter Springs Formation, Late Precambrian, Central Australia. J. Paleontology 42: 651-688.
Schopf, J. W., and E. S. Barghoorn. 1969. Microorganisms from the Late Precambrian of South Australia. J. Paleontology 43: 111-118.
K. A. Kvenvolden, and E. S. Barghoorn. 1968. Amino acids in Precambrian sediments: An assay. Proc. Nat. Acad. Sciences 59: 639-646.
Thomas, D. E. 1935. A new species of Calamopitys from the American Devonian. Bot. Gaz. 97: 334-345.
Vanuxem, L. 1842. Geology of New York. Part III. Comprising the survey of the Third Geological District, pp. 1-306. Albany, New York.
Wieland, G. B.. 1922. Devonian Plants. Science n.s. 55: 427-428.
Botany in the Academic Jungle
Sydney S. Greenfield
Rutgers University at Newark, New Jersey
The changing status of botany in American education and the tendency to de-emphasize plant science in certain institutions have been of long-standing concern to botanists. In 1952, a special committee of the Botanical Society of America reported the results of a comprehensive survey of the status of botany in 745 colleges and universities (1). This study showed that although there were many botany departments with well-developed botanical curricula, there were a great many more biology departments in which botany was de-emphasized or completely neglected. The principal causes of botany being de-emphasized, i.e., biology departments dominated by, or exclusively staffed by zoologists with little or no understanding or interest in botany, unbalanced and misleading biology courses, and administrative lack of understanding of the importance of botany, were clearly indicated by this study.
Since 1952, a number of developments have caused a worsening of an already bad situation. The A.I.B.S. and to a greater extent C.U.E.B.S. have seemed to attract some ardent propagandists for "innovative" changes, "core curricula," and some weird approaches to restructuring and teaching biology. Some of these faddists present their biologically and educationally unsound views with a dedicated ferocity exceeding that of the most ardent evangelists or political propagandists. The so-called "integrated" approach to general biology and to "core curricula" is advocated in absolute imperative terms. Any critical opposition is vigorously denounced as backward or old-fashioned, and anyone daring to criticize these self-styled "mod-ern" biologists is quickly labelled as obsolete.
Actually, the fully integrated approach is very unsound biology. It leads either to a completely zoological discussion with an occasional reference to plants as if they were animals, or to a very fragmented and illogical approach to organisms. Instead of giving the student a clear under-standing of the structure, growth, development, and physiology of a whole plant as opposed to that of a whole animal, the so-called integrated approach gives a forced and false picture of the similarities of plants and animals and tends to neglect, their differences. A giraffe simply is not built like, does not look like, and does not function like an oak tree, and no amount of revolutionary zeal or educational huckstering will make them alike. Of course, when discussing cellular or molecular biology, genetics, ecology, and evolution, wherein there are general principles applicable to both plants and animals, it is entirely valid to discuss these with both plant and animal examples. But to discuss the diversity of organisms, and the basic structure, physiology, and reproduction of both plants and animals together can only lead to confusion, and to the de-emphasis or elimination of the biology of plants.
Because of the pressure to integrate biology and due to the current academic turmoil wherein change is often mistaken for progress, the status of botany in American colleges and universities has steadily worsened. In recent years, because of weird and unnatural restructuring of departments, a number of botany departments have disappeared. Serious concern about this critical situation has been expressed in the excellent article by William Stern in the June 1969 issue of Plant Science Bulletin ('2) , and the responses to is on pp. 4-5 in the December 1969 issue; as well as in the article by W. H. Eshbaugh and T. K. Wilson in the December 1969 issue of BioScience (3).
If botany is to survive so that students may be allowed the opportunity to study it, and so that it will be possible to choose careers in teaching and research in botany, and so that botany and botanists may make their much needed contributions to our society, the destructive trends to eliminate plant studies must be reversed. It would seem obligatory for all botanists not just to teach and do research, but to live up to their professional responsibility to see that botany is maintained and advanced in proper development in the schools, colleges, and universities. Unfortunately, some botanists have contributed to the demise of botany by apathy or by accepting the propaganda of the so-called "new biology" along with some absurd administrative restructuring.
We need to educate ourselves and our colleagues with regard to the basic importance of botany and to the fallacies of the new bandwagon biology constantly advocated by pressure groups.
We need, in particular, to focus on the fallacies of the fully integrated approach in biology courses or in so-called "core curricula." Let us make it clear that it is far more important and valuable for the student to try to under-stand the plant as a wholly integrated functional unit in contrast to the animal as a whole functional unit. than to enumerate for him so-called "principles" or "concepts" by which fragments of their respectively different existences are brought together in a highly artificial framework. Students who are taught the anatomy and physiology of plants and animals together cannot possibly have a clear understanding of either or both. The circulatory system of a mammal and the vascular system of an angiosperm are not alike in structure or operation.
The fallacy of confusing plants and animals in biology is not new, as Agnes Arber (4) has clearly indicated:
The misuse of an analogy by pressing it to the point at which it is confused with an identity, is one to which biological thought is peculiarly liable. It beset the comparison between animals and plants, which was a sheet anchor of Greek biology—a comparison which would have been helpful if it had been kept in its place, but which was carried so far that it led to serious misunderstanding of vegetable structure. Marcello Malpighi, in the seventeenth century, was one of those who placed too much reliance on this resemblance. Having met with great difficulties in the anatomical studies of the higher animals, he turned to plants, in the hope that these simpler creatures would reveal clues to animal anatomy. Though he failed to unravel his puzzles by this means, his results showed how valuable even a mistaken analogy may be, for, in pursuing it, he founded, incidentally, the science of plant anatomy. Nehemiah Grew, Malpighi's English contemporary, summed up the limitation of the plant-animal analogy in the words: 'If any one shall require the Similitude to hold in every Thing; he would not have a Plant to resemble, but to be, an Animal.'
That plants and animals differ in phylogeny, diversity, anatomy, and physiology, etc., should logically dictate that they be studied separately, but this does not preclude the possibility of developing a good introductory general biology course. Indeed, a number of general biology courses and textbooks are based on this premise. Biologists may differ as to relative emphasis and as to specific content and balance, but the textbooks and courses that would seem to be taking a scientifically and educationally valid approach are those that recognize three major component areas of the general biology course.
In addition to the biology of plants, and the biology of animals as such, which form two major component areas, there is a third component area in which biology can legitimately and properly be taught by an integrated approach. This third component consists of the areas of molecular and cellular biology, genetics, evolution, and ecology, wherein there are unifying principles applicable to organisms in general. But because these areas have made much progress and received much emphasis in our time, we should not delude ourselves or our students into thinking that they represent all or even the major portion of biology.
We need to point out that integration or synthesis of knowledge into conceptual frameworks is only suitable for
advanced students, not for beginners. Synthesis is a step in thinking that presupposes prior analytical thinking. A basic fallacy of the so-called integrated biology courses and core curricula lies in the fact that they attempt to pro-duce a synthesis of knowledge before there is any analyzed and ordered knowledge to integrate.
Analysis of plant biology and of animal biology separately is deprecated with great scorn by those who pro-claim that the integrated approach is modern and represents the best approach for biologists of the future. The fallacy of the integrated approach is neither modern nor constructive. Actually, it results in a highly exaggerated and distorted picture of the true nature of the biological sciences, and is not only destructive of botany but is often detrimental to zoology as well.
An examination of some textbooks based on the integrated approach shows the fallacy of the method. These texts usually show an enormous prejudice in favor of the truly general biological areas, but try as they may, the authors simply cannot integrate plants and animals. Chap-ter headings may sound "principled," "conceptualized," or integrated, but the text typically consists of a patchwork of alternating paragraphs or sections on plants and animals, and usually with very little attention to plants. Consider the absurdity of studying digestion in stomach and intestines along with leaves and venus flytraps, and then transport with xylem, phloem, and blood vessels. Outlandish as it may seem, some of these texts are widely used in the colleges. Unfortunately, logic and validity in science teaching are often less successful than false analogies and educational huckstering.
Considering the vital importance of plants and plant science to our civilization and to liberal arts and pre-professional programs, the de-emphasis of plant biology and the virtual elimination of botany from many colleges and universities should be a matter of serious concern to everyone interested in American education. The very existence of botany as an academic discipline and of opportunities for young people to pursue careers and make contributions to teaching and research in botany are seriously threatened.
The failure to provide adequately balanced biology courses and the de-emphasis of botany in high schools and colleges result in a spiral decline in interest and, there-fore, enrollment in botany. Moreover, the failure of biology departments to allow adequate development of botanical courses further inhibits interest and denies opportunity for botanical studies for those who might be interested. The detrimental effects of the neglect of plant science in the schools and colleges become increasingly obvious. Although there are still some excellent botany departments with well-developed undergraduate and graduate programs, there are ever-fewer places where a student can get a good undergraduate or graduate education in botany, and there is a steady decline in the number of institutions where young Ph.D.s in many fundamental fields of botany can find employment and opportunities to use their training. This critical situation can hardly be ignored by responsible professional botanists.
The incongruity of the disparagement of botany in a biology program is astonishing in view of the fundamental importance of plants and plant science to our very existence, to our economic and cultural life, to agriculture and medicine. Moreover, there is enormous widespread interest in plants, and plants and plant products are involved in practically every phase of human activity.
At a time when civilization is threatened by many complex social and economic problems and by deterioration of the natural environment, and because the solution to all of these problems depends to a large extent on plants and plant science, it seems the height of absurdity for botany to be de-emphasized or eliminated while other far less important and less relevant subject areas are growing rapidly in the colleges and universities. On the basis of any or every criterion, botany would seem to require a prominent place in the curriculum.
The evidence is overwhelmingly clear (1, 2, 3) that botany can only survive and be given proper emphasis in a botany department. Although there are some exceptions, in general, one must agree with Stern (2) that "from the botanical standpoint, biology departments have not been a success anywhere." Botanists should aim to see that botany is maintained and advanced in a well-developed botany department in almost every college and university.
The alleged unity of biology as a science simply does not exist, in spite of the ardent but futile attempts to redefine the new biology in monolithic molecular terms. The biological sciences remain broader in scope and have a greater diversity of divergent fields than do all of the physical sciences put together. Physics and chemistry are much more closely related to each other than are botany and zoology. Although physics and chemistry recognize their interrelationships, and courses exist in borderline fields as they do in the biological sciences, the borderline fields are not regarded as the new sacred theology nor do physicists and chemists force a fusion of their departments to the detriment of one or both sciences.
Colleges and universities are in a period of great turmoil and change. If botany is to survive, and play its proper role in American education, we must embark on a program of education and professional action. I suggest the following:
NOTES FROM THE EDITOR
With this issue my five-year term as Editor will be completed. During the period that I served as Editor, 22 issues appeared, two of which were edited by Bill Stern during the time I was out of the country on sabbatical leave. I wish to express my appreciation and thanks to Bill, to the other members of the Editorial Board, to the many officers of the Botanical Society, and to the members who have contributed in many ways to the Bulletin. I wish to thank Mr. Henry P. Grosshans, Mrs. Patricia L. Randall, and their associates in the Washington State University Office of Publications for their advice and detailed editorial assistance. Mrs. Caroline M. Cooper and her assistants in our Duplicating and Mailing Department contributed further in the important process of distribution of the completed issues.
As was announced in this column of our last issue, the new Editor is Dr. Robert W. Long, Professor of Botany and Chairman of the Department of Botany and Bacteriology of the University of South Florida, Tampa, Florida 33620.
Included with this issue is an official registration form for our forthcoming annual meeting in Edmonton, Canada. Should you require additional copies, please request them from Dr. S. N. Postlethwait, Department of Biological Science, Purdue University, Lafayette, Indiana 47907. Dr. Postlethwait is Program Director for the Botanical Society of America.
NEWS AND NOTES
Guide to Graduate Study in Botany—new edition
The current edition of the Guide was published in 1968, and the information it contains is out-of-date. The Botanical Society of America has decided to issue a new edition, to be available in the autumn of 1971. Any department in the United States or Canada offering graduate work which can culminate in a Ph.D. in some area of botany is eligible for listing. All departments included in the 1968 edition will be asked to update their listing; any department not included in the 1968 edition but wishing to be incorporated in the 1971 edition may do so by so informing the Secretary of the Society, who will then ask for the specific information needed for the listing. Secretary: Dr. Barbara F. Palser, Department of Botany, Rutgers University, New Brunswick, N.J. 08903.
Darbaker Prize in Phycology for 1971
The committee on the Darbaker Prize of the Botanical Society of America will accept nominations for an award to be announced at the annual meeting of the Society at the University of Alberta, Edmonton, Alberta, Canada, in 1971. Under the terms of the bequest, the award is to be made for meritorious work in the study of microscopical algae. The committee will base its judgment primarily on the papers published by the nominee during the last two full calendar years previous to the closing date for nominations. At present, the award will be limited to residents of North America. Only papers published in the English language will be considered. The value of the prize for 1971 will depend on the income from the trust fund, but is expected to be about $300. Nominations for the 1971 award accompanied by a statement of the merits of the case and by reprints of the publications supporting the candidacy must be received by March 1, 1971, by the Chairman of the Committee, Dr. Ruth Patrick, Department of Limnology, Academy of Natural Sciences, 19th and the Parkway, Philadelphia, Pennsylvania 19103.
Summer Research Participation in Botany for College Teachers at the University of North Carolina
The Department of Botany at the University of North Carolina, Chapel Hill, has been awarded a grant of $ 12,950 by the National Science Foundation to conduct a research participation program for college teachers during the summer of 1971. The grant provides stipends of $1,000 each for five postdoctoral participants and $750 for one pre-doctoral participant. In addition, each participant will receive a dependency and travel allowance. The program will begin June 14 and end August 21.
Any teacher of biological sciences in a U.S. college or junior college is eligible to apply. Application forms and a brochure describing the program may be secured by writing the Director of the program, Dr. Victor A. Greulach, Department of Botany, University of North Carolina, Chapel Hill, N.C. 27514.
The professors available for directing the research of participants are John N. Couch and William J. Koch in mycology; Max H. Hommersand in phycology and algal physiology; R. Malcolm Brown, Jr. in phycology and cell ultrastructure; A. J. Domnas in plant biochemistry; Tom K. Scott in plant physiology; Clifford Parks in plant genetics and chemotaxonomy; Helmut Lieth in ecology; A. E. Radford and C. Ritchie Bell in plant taxonomy and systematics; and William C. Dickison in plant morphology.
The goal of the program is to provide an opportunity to resume research activity by college teachers who have been unable to continue active investigation because of lack of time, space, or facilities.
12th Pacific Science Congress
The Australian National University, Canberra, will be the site of the 12th Pacific Science Congress, August 18-September 3, 1971. The four themes to be featured at this Congress are "Productivity and Conservation in the Pacific," "Man in the Pacific," "Environmental Quality and Resource
Management: Political, Legal and Administrative Realities," and "Geological Structure and Mineral Resources in the Pacific Area." The program will consist entirely of invited papers. Pre- and post-congress tours of Australia, the Great Barrier Reef, and of New Guinea are being planned. For further information and registration forms, write to Organizing Secretary, Twelfth Pacific Science Congress, Australian Academy of Science, Gordon St., Canberra City, A.C.T. Australia 2601.
Foreign Botanists Elected to Corresponding Membership in the Botanical Society
Knut Faegri, Professor of Systematic Botany and Plant Geography, Chairman of the Institute of Systematic Botany at the University of Bergen, Norway, is recognized as an authority on pollen analysis, particularly through his book Textbook of Pollen Analysis with J. Iverson, and as a plant geographer by his papers and a two-volume work Plants of Norway. Recently he demonstrated great versatility with his book, Principles of Pollination Ecology with L. Van der Pijl. Equally important has been his editorship of a popular science journal Naturen where he has brought science to the people. His keen mind and articulate presentation have made him a well-known figure in science in Scandinavia in areas ranging from problems of narcotics to those of science policy.
Professor Dr. Bruno Huber, now Professor Emeritus at the University of Munich, was long the Director of its Institute of Forest Botany where he attracted many students to botany by the excellence of his teaching. Aside from his administrative duties and his activity in the field of forest practice, Huber is a plant physiologist and anatomist of world-wide renown. The temperature economy of plants, physiology of bark slippage, water conduction in trees, gas exchange physiology, and conduction through the phloem have been his major areas of interest. His anatomical work on wood and bark and on conifer needles and tree ring chronology indicates the extent to which he has combined structure and function in his own activities. Other publications attest to his ecological background. His prodigious output of over 200 papers can only in-spire admiration.
We are very sorry to report that we have learned, since his election at the Business Meeting of the Botanical Society, that Dr. Huber died in the spring of 1970.
Botanical Garden at the University of British Columbia
Roy L. Taylor, Professor of Botany and Plant Science and Director of the Botanical Garden at the University of British Columbia, has received approval from the Board of Governors of the University to proceed with plans for the 77-acre Botanical Garden. Total costs for this project, which is scheduled for completion by 1981, have been estimated at somewhat over five million dollars. The main emphasis, according to Dr. Taylor, will be in the area of research and academic teaching. A research-administration center building together with some eight greenhouses will be constructed following the grounds development. In addition to the greenhouses for research and teaching, the
Gardens will feature three display houses containing tropical, temperate, and dry-habitat plants emphasizing economic and chemically useful plants.
Course in Plant Cell and Tissue Culture
A course entitled Plant Cell and Tissue Culture will be offered July 12-August 6, 1971 at the W. Alton Jones Cell Science Center, Lake Placid, New York. Although the course is intended primarily for persons holding the Ph.D., qualified graduate students will be considered if space is available. The deadline for receipt of completed applications will probably be February 1, 1971. For further details and application forms write to Dr. Donald J. Merchant, Director, W. Alton Jones Cell Science Center, P.O. Box 631, Lake Placid, N.Y. 12946.
Graduate Courses in Tropical Science for 1971
In 1971 the Organization for Tropical Studies, a consortium of 27 Latin and U.S. universities created to promote an understanding of tropical environments and their intelligent use by man, will offer its ninth consecutive year of graduate courses in tropical science in Central America. A total of eight courses will be distributed through three semesters commencing on February 1, 1971. Graduate credit for eight semester hours may be earned through the University of Costa Rica. Courses will be offered in the following disciplines: Terrestrial Biology and Ecology, Forestry, Geography, Earth Sciences, and Atmospheric Sciences. Most of the courses will be offered in Costa Rica or Guatemala, although the Earth Science course will be concentrated in the islands of the West Indies.
All of the OTS courses are field-oriented and highly intensive. The program is interdisciplinary in nature and problem-oriented. Most of the students will undertake one or more limited research projects during the training period. The faculty is selected from universities throughout the Americas, and the students are chosen on the basis of academic excellence and tropical research interests.
Most or all of the student expenses are paid under a grant from the National Science Foundation to the OTS.
Courses and closing dates for applications are indicated as follows:
An Ecological Approach November 15, 1970
Habitat Exploitation and Diversity: An
Ecological Approach with Vertebrates January 15, 1971
Costa Rican Example January 15, 1971
Recent Carbonate Sedimentation and Early
Diagenetic Processes, British West Indies March 7, 1971
Section I April 1, 1971
Section II April 1, 1971
in Selected Areas of Central America April 1, 1971
Tropical Environment .. April 1, 1971
A descriptive catalog of the courses and applications for enrollment may be obtained from: The Organization for Tropical Studies, North American Office, 5900 S.W. 73rd St., South Miami, Florida 33143.
Awards Presented at the Botanical Society's Banquet
The Darbaker Prize, awarded annually for meritorious work in microscopical algae, was presented to Bruce C. Parker (Virginia Polytechnic Institute, Blacksburg, Virginia) "for his wide-ranging and imaginative investigations which have resulted in publications that have augmented significantly our knowledge of algal environments and the chemistry of the cell walls through which algae interact with these environments." Dr. Parker received a certificate and a check for $345.
The Jeanette Siron Pelton Award, established by the Conservation and Research Foundation to recognize exceptionally imaginative published contributions in the field of experimental plant morphology, was awarded to Claude W. Wardlaw, Emeritus Professor of Botany, University of Manchester, England. Professor Wardlaw thus became the second person to be honored by this award, which carries a stipend of $1,000. The citation accompanying the award stated: "Experimental morphology is a synthetic science and draws its practitioners from the full spectrum of plant science. It is completely fitting that this award be presented to a man whose scholarship epitomizes the style of the discipline. Professor Wardlaw's accomplishments are many and varied, ranging from authoritative works on the diseases of tropical plants to investigations of morphogenesis in pteridophytes and angiosperms. Perhaps his greatest contribution has been made through his various books in which he has effectively argued for a broad philosophical view of developmental problems. He has outlined many of the basic morphogenetic problems during the past two decades, and his eloquent pleas for an integrative approach to the study of plant development will provide a hallmark for all future investigators."
The New York Botanical Garden Award was presented to C. Leo Hitchcock (University of Washington), Arthur Cronquist (New York Botanical Garden), Marion Ownbey (Washington State University), and J. W. Thompson (Seattle, Washington) for their five-volume work, Vascular Plants of the Pacific Northwest. Although publication began in 1955, the final volume was published in 1969 so that this monumental work has just been completed.
The Henry Allan Gleason Award of the New York Botanical Garden, presented annually to the author of an outstanding recent publication in botany—usually plant taxonomy, phytogeography, or ecology, went to George Willard Martin (State University of Iowa). In presenting this award, Dr. W. C. Steere, Executive Director of the Garden, stated in part that "the 1970 award is presented to Dr. Martin in recognition of his life-long work on slime molds, culminating in the recent world mono-graph, The Myxomycetes. This is the first time the Gleason Award has been given to a cryptogamic botanist, and it is appropriate that we here recognize Dr. Martin's many years of study on this difficult group of plants."
The Jessie M. Greenman Award, established in 1968 by the Alumni Association of the Missouri Botanical Gar-den and awarded annually for the best doctorate thesis in plant systematics published during the preceding year, was awarded to Dr. Beryl S. Vuilleumier of the Gray Her-barium at Harvard University for the thesis entitled "The Systematics and Evolution of Perezia Section Perezia (Compositae) ."
The Mary Soper Pope Medal of the Cranbrook Institute of Science, Michigan, was presented to William C. Steere, Director of the New York Botanical Garden, for his out-standing contributions to the field of botany.
The George R. Cooley Award, presented by the American Society of Plant Taxonomists for the best paper presented during the current meetings, went to Lorin I. Nevling, Jr. and Thomas F. Elias of Harvard University for their paper entitled "Calliandra Pollinia and Systematic Implications."
The annual Merit Awards of the Botanical Society, initiated in 1956 and presented to persons judged to have made outstanding contributions to botanical science, went to four eminently qualified botanists:
Charles Drechsler (Plant Industry Station, Beltsville) "though one of the leading authorities on root diseases of truck crops, he is best known for his masterful work on the zoophagous fungi and particularly the nematode-catching fungi which he has illustrated with beautiful artistry."
Arthur W. Galston (Yale University), "superb teacher, creative investigator in plant hormones, and bold fighter to prevent misuse of such substances."
James M. Schopf (U.S. Geological Survey, Ohio State University), "his studies of fossil plants, and especially his work on the petrology of coal, are among the definitive works in this field."
Albert C. Smith (until recently University of Hawaii, now University of Massachusetts), "his monumental work on the Flora of the Fiji Islands has set exceptionally high standards and placed him in the front ranks of the students of the systematics of higher plants."
The Department of Botany at the University of British Columbia announces the appointment of Dr. Ronald E. Foreman (Ph.D., Berkeley). Dr. Foreman's special field is in physiological ecology. Antero Vaarma, a bryologist and formerly Director of the Botanical Institute of the University of Turku, Finland, is a visiting professor this year at the University of British Columbia. Three members of the UBC botany faculty are currently on leave: G. H. N. Towers, Professor of Botany and Head of the Department, is spending most of his leave at the University of East Anglia, Norwich, England; Robert E. Scagel, Professor of Botany and Associate Dean of the Faculty of Science, will spend most of his leave in the Vancouver area; E. Bruce Tregtulna, Associate Professor of Botany, is at the Experimental Station in Harpenden (Hartsf.), England. During Dr. Towers' absence, Clayton O. Person, Professor of Botany, is the Acting Head of the Department.
SOLBRIG, OTTO T. Principles and Methods of Plant Bio-systematics. Macmillan, Toronto. 1970. viii + 226 pp., illus. $9.95.
"The objective of the author," as stated in the Preface, "is to present the theoretical and technical aspects of systematics that are not adequately covered in most of the presently available textbooks." He designed his book "to be used not only as a textbook in taxonomy courses devoted to the more experimental aspects of the field, but also as a companion to any of the many fine plant taxonomy books being used...."
To achieve this purpose, he divided his slim volume into two parts of about equal length: Part I, "The Process of Speciation -and the Forces that Control It" with seven chapters dealing (somewhat simply) with the history and development of evolutionary theory, resumes of our knowledge of genetics, plant geography, speciation, hybridization, and the problem of the definition of terms such as species. Part II, "Some Techniques for the Study of Species," has five chapters dealing with various approaches to such study—genetics, cytology, various biochemical techniques, the uses of statistics—and a concluding chapter which looks somewhat to the future.
Solbrig's book is lucidly written, for the most part, and should be comprehensible to the group he has set out to address. Only when he gets into his favorite areas, as in chapter nine, Cytology, does his narrative become somewhat abstruse and his illustrations, both textual and figurative (e.g., Figs. 9-3 and 9-4), somewhat mystifying and insufficiently explicative. His discussion of the species concept was quite satisfying, and the discussions of breeding systems and genetics in general were thorough. The work of the Carnegie Institution group (Clausen, Keck, and Hiesey) on phenetic variability is discussed, as well as the work of Macmillan on prairie grasses. The latter, I've always felt, has been, wrongly, rather neglected by others.
Nevertheless, I went away from the book vaguely dissatisfied and not quite certain why. In a way, I think it is because, in many instances, the book takes you, like Moses, to within sight of the Promised Land, but leaves you without, fated never to enter. For example, he mentions the concepts of Camp and Gilly's 1943 paper but doesn't really develop a discussion of their interesting, but unfortunately abortive, attempt at a new nomenclature. Likewise, Turesson's concepts about ecospecies, ecotypes, etc., are introduced but never developed, even though the work of Claussen et al. and Macmillan is next discussed. The basis for understanding how new and different this sort of work was, and is, is not quite thoroughly enough established.
More disappointing, to me, was Part II, on techniques. I rather expected a book with "Methods" in the title to discuss methods in extenso, with details of technique. But this is not a "how-to-do-it" book. It outlines various techniques for studying populational differences, such as gel electrophoresis of proteins, for example, or chromatography, but does not really discuss how to do such a study or the physico-chemical bases for such methods of study. Genetic and cytological techniques receive more attention than the various chemical and statistical approaches, but even here, the beginning student does not get any sense of how one organizes such studies.
There is a reasonably extensive bibliography of books and journal articles, but there is no discussion of how to enter and utilize the literature. Nor is there any discussion of annual review series, such as the one edited by Dobzhansky et al., Evolutionary Biology, or books and series on phytochemistry, etc. I think a book aimed at the undergraduate would point out the relevant journals, annual series, etc., explicitly.
The reading of this book brought to me once again the realization that, for the most part, biosystematic and evolutionary studies deal with the mature organism, the endpoint of ontogenetic processes. Solbrig alludes to this now and again but, again, does not develop the idea fully. Here we have thousands of plant species possessing the same glycolytic pathway, electron transport pathway, photo- systems I and II, etc., the same few growth regulators: IAA, abscissic acid, a few gibberellins and cytokinins, perhaps; phytochrome, and so on. And yet how different they all are! How little we know of the effects attendant upon the starting and stopping of growth regulator pro- duction and transport; of the subtle shades of difference in response to the functioning of the phytochrome system, etc. When we can characterize and differentiate related species by a knowledge of the differences in the ongoing ontogeneses, and be able to say how the ontogenetic processes in these populations change with time, then we will really be able to say we know what evolution is. H. David Hammond
HARTOG, C. DEN. 1970. The Sea-Grasses of the World.
North-Holland Publishing Company, Amsterdam. 275 pp., 63 figs., 31 pls. $15.40.
This monograph on the marine Angiosperms constitutes the first worldwide coverage on the group and fills a recognized gap. Treatment of taxonomic, geographical, and ecological data is exhaustive, well written and will be easily used. Maps displaying geographic distribution for each genus are given. There is an excellent discussion on the phylogenetic origin of the seagrasses.
Keys to subfamilies, genera, and species are clear and well written. For the most part keys are based on vegetative characters. This by itself should stimulate their use in those geographic areas, such as the Indo-Pacific region, where species identification has been difficult owing to a very diverse literature.
The author has used one or two characters in delimiting species in certain genera. For instance, in the subgenus Zosterella, a new species of Zostera, Z. americana, has been erected solely on the basis of two characters, leaf tip shape and shape of retinacula (flap along spadix margins), both of which seem to intergrade with the Japanese species Z. japonica. This practice has been carried to the extreme in the tropical genus Halodule, where several species were erected solely on the basis of the shape of the leaf tip.
The book will be welcomed by anyone working or contemplating work on seagrasses.
Ronald C. Phillips