Canadian Association of Palynologists
 

Resources for the
Identification of Plant Macroremains

by
Alwynne B. Beaudoin
Archaeological Survey, Provincial Museum of Alberta
Edmonton, Alberta, Canada

Introduction

In July 2000, a graduate student posed the following request to the Quaternary discussion list: "I was hoping to get some information on some good texts to begin with for the identification of seeds and fruits recovered from a palaeoecological context." I posted a lengthy reply and reference list. Because the student was working on material from the far northwest of Canada, my discussion focussed specifically on that region. Mary Vetter (CAP Newsletter Editor) asked me to fine-tune it a little for this issue of the Newsletter. The following discussion is basically a slightly amended (i.e., the spelling errors corrected!) and expanded version of that reply, hence its very informal and chatty nature. The list of references is by no means complete. I trust, however, that the information may be useful to other Newsletter readers. Many of us working with pollen from Quaternary sites also work with plant macroremains. The identification of these can often be difficult if you are not sure where to start!

Response

The two basic references to start with are Berglund's (1986) book (especially the chapter by Wasylikowa) and Warner's (1990) compilation on Methods in Quaternary Ecology.

I'd recommend Warner's book to anyone working in Canadian Quaternary palaeoecological studies. Although ten years' old, the chapters contain useful introductions to the various types of macro- and microremains that are the focus of palaeoecological work. The chapters are not exhaustive, but are good reviews, and offer a place to start for an introduction to the literature. It is still available from the Geological Association of Canada through their on-line ordering system at their website. Go to http://www.esd.mun.ca/~gac/ and look under "Publications". From what I can see here, this volume looks as if it is on sale at the moment.

Your encounter with "macrobotanicals" will undoubtedly involve other macroremains too (e.g., molluscs, ostracodes, and insect remains – especially if you are working with lacustrine, wetland or fluvial sediments). The chapters in Warner's book provide a helpful illustrated guide to some of the other odder critters that you may find. These also may yield valuable palaeoecological information. Hence, I have included in the list below a couple of references to mollusc identification, and one of Delorme's papers on ostracodes (there are a whole series of these).

Besides these, there is a short volume produced by Agriculture Canada about ten years ago on macroremains in peatlands (Lévesque et al. 1988). This can help you to characterize some macroremains, although I have not found that it gives sufficient detail for precise identifications. However, the volume does show material besides seeds (such as wood fragments, leaf fragments, roots, etc.). These illustrations may often be helpful when you are at the stage of trying to decide whether the thing swimming into focus under the dissecting ‘scope is "animal, vegetable, or mineral"! These other macroremains (insects, moss leaves etc.) may often require the assistance of other specialists to identify.

The list below includes several texts that deal with "seed" (sensu lato) identifications. The two basic texts for work here are Martin and Barkley (1961) and Montgomery (1977). Additional texts deal with other aspects of the flora, such as weed seeds [e.g., Delorit (1970), and Davis (1993)] and tree seeds (USDA Forest Service 1974). The images in Martin and Barkley are very good and it is still, in my view, the best text around. It's been out of print for years and I was pleased to hear recently that it was being republished. (See http://www.blackburnpress.com/biobook2.html for details and ordering information). The images in Montgomery are not as good, and he has a terminology for describing seed shapes that I find difficult to follow or apply at times.

There are several texts listed below that deal with seeds from other areas in North America and Europe. These may be of value, at least as a guide to the range of forms that may be found within a Family or Genus. However, they often don't have the range of species that we encounter in western North America. Beijerinck (1947) and Berggren (1969 and 1981) fall into this group. Beijerinck (1947) consists mainly of line drawings. I also have a faded copy of a publication by Körber-Grohne (1991) dealing mainly with grasses. Much of this literature is out-of-print and unobtainable, except perhaps by inter-library loan, and circulates among the seedy community in a form of samizdat, copies getting progressively more illegible!

Although a bit dated now, Delcourt et al. (1979) is also a good starting place for guidance to the (mainly North American) literature on seed identification. Their compilation lists references by Family, so it is especially useful if you have already narrowed down the assignment. This listing also contains references for other types of plant material (e.g., phytoliths, wood, and charcoal).

There are, however, several problems with many of these texts, as follows:

  1. For one thing, they usually illustrate "fresh" material, often herbarium specimens. These often bear little relation to the dismal worn material that we work with in the palaeoecological record. For instance, Carex species are identified partly on the characteristics of the perigynia. This is rarely present in sub-fossil material, in my experience, even when preservation is good. That is, subfossil material may be missing a few outer layers, making identification difficult. In addition, subfossil material may be different in colour from fresh material.
  2. Many of these texts (e.g., Delorit, Flood, and Davis) were produced to help agronomists and similar specialists identify weed seeds. Hence the wetland taxa that are such a prominent focus of palaeoecological work are often not well covered.
  3. The geographic focus of these texts is not northwest Canada, and may not be North America. Hence, they do not illustrate many taxa that we find here. There does seem to be a strong geographic variation in the morphological (specifically size) characteristics of seeds even within the same species. For example, seeds that I have measured provide different size ranges from those shown by Montgomery even for the same species. This may relate to geographic (clinal) variation within a taxon, degree of seed maturity, and the method of measurement. In addition, subfossil seeds can vary (usually smaller) in size than fresh material. Hence, be leery of using seed size as a defining criterion.
Basically, there isn't a good text for western Canadian seeds in Quaternary palaeoecological context. [Hmmm, maybe I should write one?!! :-) ]

Your problems can be compounded if the seeds you are dealing with are fragmentary and carbonized as well. In this case, the archaeobotanical literature can be useful. Pearsall (1989) covers much of this, and I direct your attention especially to her Chapter 3 ("Identification and Interpretation of Macroremains", pp. 107-243). Archaeobotanists are often used to working with poorly preserved material, carbonized samples, or partial remains. However, this field is also not without problems. Archaeobotanical studies often focus on crop or gathered plants (in North America, plants such as Iva and Chenopodium). Again, these are usually upland terrestrial plants, rather than wetland plants. Hence they do not provide a guide to the range of material that you might find in a deposit accumulated as a result of fluvial, ecological, or geomorphic processes, as opposed to an archaeological site context.

As with pollen analysis, or any other identification procedure, there is no substitute for a good reference collection to help you. The texts, illustrations and descriptions can help you narrow down the taxonomic assignment, but to be certain, you really need to compare your samples with reference material. Fresh seeds from the reference collection can also be mistreated in various ways to simulate degradation and give a better match the subfossil material. I curate an extensive Seed Reference Collection at the Provincial Museum, and scholars are welcome to visit and use it in their work. Please contact me (e-mail address below) if you want access to this collection.

You should be aware that macroremains are often illustrated in various palaeoecological papers. Many research papers contain good pictures, especially SEM images, of seeds and other macroremains. Some papers may also concentrate on pollen, thereby using two indicator types for palaeoecological investigation. The papers by John Matthews, many of which are focussed on sites in your field region, often contain good SEM and LM illustrations of macroremains (notably seeds and insects). Other papers R. G. Baker and by B. G. Warner also often incorporate illustrations of macroremains. Sometimes, modern and subfossil specimens are illustrated; this is particularly useful as a guide to the type of degradation that may be encountered. Birks (1980) discusses the pathways by which seeds get into Quaternary lake sediments, and includes drawings of some seeds and macroremains.

Finally, many Floras and Field Guides also contain seed illustrations that can be very helpful, although seeds are not their main focus. In some plant taxa, such as the Cyperaceae, seeds may be quite important for plant identification purposes. For example, Hurd et al. (1998) contains fine illustrations (both colour photos and drawings) of seeds of 114 Carex species as part of the critical identification components. Below, I have listed two monographs by Brayshaw that have beautiful drawings of plants and seeds. Since they focus on wetland taxa from western Canada, I think you'd find them both useful. Also on the wetland theme, Hurd et al. (1994) contains generally good photographs, some in colour, of twenty-three Juncus species and their seeds. For grasses, Dore and McNeill (1980) includes many photographs of fresh grass seeds. However, the best drawings and illustrations are often found in Floras that may have been published decades ago!

And, as an aside, for non-biologists, the terminology associated with "seeds" can be confusing. For instance, what's the difference between a seed, fruit, achene, nut, nutlet, samara, and caryopsis? Often terms are used quite loosely, and palaeoecologists sometimes use "seed" as a shorthand way of referring to a whole gamut of macroremains, only some of which are strictly seeds. Often, we are looking at the structures surrounding the seed, rather than the seed itself. I have found the monograph by Spjut (1994) very helpful for sorting out this terminology. Harris and Harris (1994) contains a brief but useful introduction to fruit terminology (pp. 182-188).

For any seed types that you do identify, I recommend that you do a "taxonomic diagnosis". That is, a detailed description of the morphology of your specimens, comparison with published descriptions and reference material, and summary of the criteria on which you make a taxonomic assignment. This diagnosis could be accompanied by drawings, and LM and SEM photos. This information would be helpful as part of your thesis appendices. (Especially useful if someone questions your taxonomic assignments later!). For an example of this, accompanied by some superb SEM images, see the appendices in Yansa and Basinger (1999).

The best way to learn to identify seeds, as with pollen or any other macroremains, is by long hours at the microscope, spent making lots of drawings and descriptions of both your specimens and the comparative reference material. Drawing specimens is very good training in observation; it forces you to examine the specimen really carefully. I have found that drawing and describing each taxon on a 3"x5" file card is a constructive exercise. Even in these days of digital everything, such cards will still be a handy aide-mémoire.

There are not many studies focussed on macroremains in palaeoecological context, at least in Canada. Certainly, plant macroremains have received far less attention than pollen. The work of Warner, Baker, and Matthews forms a substantial amount of the literature that is available, especially for western North America. Peter Kuhry has also produced several papers dealing with plant macroremains in boreal Canada. Bob Vance found plant macroremains more useful than pollen for the investigation of changing water levels at Chappice Lake in southern Alberta. Below, as a starting point, I have included a few references to some of this work. Note that this is not a complete list by any means; all these researchers have completed many other papers and, of course, there is work by other people too.

Reference list for identifications

Beijerinck, W. 1947 Zadenatlas der Nederlandsche Flora. H. Veenman and Zonen, The Netherlands. 316 pp.

Berggren, G. 1981 Atlas of Seeds and Small Fruits of Northwest European Plant Species Part 3 Salicaceae - Cruciferae. Swedish Natural Science Research Council. 259 pp.

Berggren, G. 1969 Atlas of Seeds and Small Fruits of Northwest European Plant Species Part 2 Cyperaceae. Swedish Natural Science Research Council. 68 pp.

Berglund, B. E. (editor) 1986 Handbook of Holocene Paleoecology and Palaeohydrology. John Wiley, New York, U.S.A. xxiv + 869 pp.

Brayshaw, T. C. 1989 Buttercups, Waterlilies and Their Relatives in British Columbia. Royal British Columbia Museum Memoir No. 1. Royal British Columbia Museum, Victoria, British Columbia. viii + 253 pp.

Brayshaw, T. C. 1985 Pondweeds and Bur-reeds, and their Relatives of British Columbia. Occasional Papers Series No. 26. British Columbia Provincial Museum, Victoria, British Columbia. vi + 167 pp.

Burch, J. B. 1962 How To Know The Eastern Land Snails. Pictured-Key Nature Series. Wm. C. Brown, Dubuque, Iowa. 214 pp.

Clarke, A. H. 1981 The Freshwater Molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, Ottawa, Ontario. 446 pp.

Davis, L. W. 1993 Weed Seeds of the Great Plains: A Handbook for Identification. Cooperative Extension Service of Kansas State University. University Press of Kansas, Lawrence, Kansas. vi + 145 pp.

Delcourt, P. A., O. K. Davis, and R. C. Bright 1979 Bibliography of Taxonomic Literature for the Identification of Fruits, Seeds, and Vegetative Plant Fragments. Environmental Sciences Division, Publication No. 1328. Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA. 84 pp.

Delorit, R. J. 1970 Illustrated Taxonomy of Weed Seeds. Agronomy Publications, River Falls, Wisconsin. 175 pp.

Delorit, R. J., and C. R. Gunn 1986 Seeds of the Continental United States Legumes (Fabaceae). Agronomy Publications, River Falls, Wisconsin. 134 pp.

Delorme, L. D. 1970 Freshwater Ostracodes of Canada. Part III. Family Candonidae. Canadian Journal of Zoology 48:1099-1127.

Dore, W. G., and J. McNeill 1980 Grasses of Ontario. Research Branch, Agriculture Canada, Monograph 26. 566 pp.

Elias, S. A., and O. Pollak 1987 Photographic Atlas and Key to Windblown Seeds of Alpine Plants from Niwot Ridge, Front Range, Colorado, USA. Institute of Arctic and Alpine Research, University of Colorado, Occasional Paper No. 45. Institute of Arctic and Alpine Research, Boulder, Colorado, USA. iv + 28 pp.

Flood, R. J. 1986 Seed Identification Handbook. National Institute of Agricultural Botany, Cambridge, UK. 72 pp.

Harris, J. G., and M. W. Harris 1994 Plant Identification Terminology: An Illustrated Glossary. Spring Lake Publishing, Spring Lake, Utah, USA. ix + 197 pp.

Hurd, E. G., S. Goodrich and N. L. Shaw 1994 Field Guide to Intermountain Rushes. General Technical Report INT-306. Intermountain Research Station, Ogden, Utah. Forest Service, USDA. 56 pp.

Hurd, E. G., N. L. Shaw, J. Mastrogiuseppe, L. C. Smithman, S. Goodrich 1998 Field Guide to Intermountain Sedges. General Technical Report RMRS-GTR-10. Rocky Mountain Research Station, Ogden, Utah. Forest Service, USDA. 282 pp.

Körber-Grohne, U. 1991 Bestimmungsschüssel für subfossile Graminee-Früchte. In Probleme der Küstendforschung im Südlichen Nordseegebiet. Band 18: 169-234. [In German and English]

Lévesque, P. E. M., H. Dinel, and A. Larouche 1988 Guide to the Identification of Plant Macrofossils in Canadian Peatlands. Land Resource Centre, Ottawa, Ontario. Research Branch, Agriculture Canada. Publication No. 1817. v + 65 pp.

Martin, A. C., and W. D. Barkley 1961 Seed Identification Manual. University of California Press, Berkeley, California, USA. 221 pp.

Montgomery, F. H. 1977 Seeds and Fruits of Plants of Eastern Canada and Northeastern United States. University of Toronto Press, Toronto, Ontario. 232 pp.

Pearsall, D. M. 1989 Paleoethnobotany: A Handbook of Procedures. Academic Press, San Diego USA, 470 pp.

Spjut, Richard W. 1994 A Systematic Treatment of Fruit Types. Memoirs of the New York Botanical Garden Volume 70. 181 pp.

US Department of Agriculture, Forest Service 1974 Seeds of Woody Plants in the United States. USDA Agriculture Handbook 450. viii + 883 pp.

Warner, B. G. (editor) 1990 Methods in Quaternary Ecology. Geoscience Canada Reprint Series 5. Geological Association of Canada. 170 pp.

Wasylikowa, K. 1986 Analysis of Fossil Fruits and Seeds. In Handbook of Palaeoecology, edited by B. E. Berglund, pp. 571-590. John Wiley, Chichester, England.

Reference list of selected palaeoecological studies using macroremains

Baker, R. G. 1976 Late Quaternary History of the Yellowstone Lake Basin, Wyoming. United States Geological Survey Professional Paper 729-E. 48 pp.

Baker, R. G., E. A. Bettis III, D. G. Horton, C. A. Chumley, L. A. Gonzalez, and M. K. Reagan 1996 Holocene Paleoenvironments of Northeastern Iowa. Ecological Monographs 66(2): 203-234.

Birks, H. H. 1980 Plant Macrofossils in Quaternary Lake Sediments. Archiv für Hydrobiologie 15:1-60.

Dyke, A. S., and J. V. Matthews Jr 1987 Stratigraphy and Paleoecology of Quaternary Sediments along Pasley River, Boothia Peninsula, Central Canadian Arctic. Géographie physique et Quaternaire 41:323-344.

Karrow, P. F., and B. G. Warner 1984 A Subsurface Middle Wisconsinan Interstadial Site at Waterloo, Ontario, Canada. Boreas 13:67-85.

Kuhry, P., L. A. Halsey, S. E. Bayley, and D. H. Vitt 1992 Peatland Development in Relation to Holocene Climatic Change in Manitoba and Saskatchewan (Canada). Canadian Journal of Botany 29:1070-1090.

Kuhry, P., B. J. Nicholson, L. D. Gignac, D. H. Vitt, and S. E. Bayley 1993 Development of Sphagnum-dominated Peatlands in Boreal Continental Canada. Canadian Journal of Botany 71:10-22.

Matthews Jr., J. V., C. E. Schweger, and J. A. Janssens 1990 The Last (Koy-Yukon) Interglaciation in the Northern Yukon: Evidence from Unit 4 at Ch'ijee's Bluff, Bluefish Basin. Géographie physique et Quaternaire 44:341-362.

Vance, R. E., J. J. Clague, and R. W. Mathewes 1993 Holocene Paleohydrology of a Hypersaline Lake in Southeastern Alberta. Journal of Paleolimnology 8:103-120.

Warner, B. G., R. J. Hebda, and B. J. Hann 1984 Postglacial Paleoecological History of a Cedar Swamp, Manitoulin Island, Ontario, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 45:301-345.

Warner, B. G., P. F. Karrow, A. V. Morgan, and A. Morgan 1987 Plant and Insect Fossils from Nipissing Sediments Along the Goulais River, Southeastern Lake Superior. Canadian Journal of Earth Sciences 24: 1526-1536.

Warner, B. G., R. W. Mathewes, and J. J. Clague 1982 Ice-Free Conditions on the Queen Charlotte Islands, British Columbia, at the Height of Late Wisconsin Glaciation. Science 218:675-677.

Yansa, C. H., and J. F. Basinger 1999 A Postglacial Plant Macrofossil Record of Vegetation and Climate Change in Southern Saskatchewan. In Holocene Climate and Environmental Change in the Palliser Triangle: A Geoscientific Context for Evaluating the Impacts of Climate Change on the Southern Canadian Prairies, edited by D. S. Lemmen and R. E. Vance, pp. 139-172. Geological Survey of Canada Bulletin 534. Ottawa, Ontario.

Contact: Alwynne B. Beaudoin, Archaeological Survey, Provincial Museum of Alberta Edmonton, Alberta. E-mail: bluebulrush@gmail.com
 



  This article first appeared in CAP Newsletter 23(2):7-11, 2000.

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