Interpreting waterlogged plant assemblages

Waterlogged plant assemblages may consist of economic plants used by the site's population as well as plant remains from the natural environment of the site, which have not been in a direct contact with man. For the archaeobotanical interpretation it is necessary to distinguish between the two sources. While for cultivated plants this is obvious, this must be validated and discussed for most of the wild plant species.

For that, in a first step the entire assemblage of subfossile wild plant species has to be grouped in ecological groups to reconstruct the different habitats from where they might have come. These habitats must have been at the site itself or within the action scope of the people. A second step is, to study the natural vegetation and the vegetation history at the site. This can be done by botanical-stratigraphical analyses or pollen analyses in drillings or profiles.

In the case of wetland sites, species from moorland, riverside or lakeshore habitats as well as most of the aquatic plant species normally are parts of the natural environment and probably have not been in a direct contact with man. Of course there are exceptions like the water chestnut (Trapa natans) which could be collected as a food plant. In the case of urban or rural dryland sites with waterlogged sediments, remains of ruderal species often are found, that have been growing directly at the site.

On the other hand, plant remains from habitats beyond the site must have been brought in by man or by animals and for that must be considered to have economic aspects. Some of the most important groups are:

1. Woodland, hedges and forest edges. These habitats offer a lot of useful plants like collected wild fruits and nuts like raspberry, strawberry, blackberry, black elder, hazelnut and others. Besides, different medical plants and dye plants grow in these areas. Wood delivers building material and fuel, bark material for different fabrics.

2. Grassland. Remains from fresh and dryer grassland may derive from animal fodder, brought into the site by people or derived from animal dung. Plants from wet meadows could have been used as bedding in stables.

3. Field weeds and ruderals. Uncharred seeds and fruits from field weeds and ruderals may derive directly from crop processing, giving evidence of where in the site these activities were performed. On the other hand they might have been discarded on rubbish heaps, in wells or at other places.

Economic aspects of some important tissue types

Cereals

Cereal Bran

Bran has mostly been found in cesspits, latrines and human coprolites as well as in cultural layers where it proves, that cereal products have been eaten. The size of the fragments show how fine the grains have been ground. If well preserved transversal cells exist, information about the ground cereal species may even be available. Bran has also been identified on uncarbonized surfaces of charred porridge. Some porridge crusts have been found at the bottom of neolithic ceramic pots while others showed impressions of bowls of wood or bark.

References among others:

• Dickson & Dickson 1979
• Dickson 1989, pl. 1,
• Greig 1981,
• Huntley & Hillam 2000,
• Kenward & Hall 1995, fig. 193,
• Maier, U. 2001, table 4,
• Maier, S. 1988, fig. 3

Cereal Chaff

Of great interest are uncharred chaff concentrations still situated where they have been produced, because they may provide important information about plant processing. When cereals are processed, straw as well as free-threshing rachis internodes and a few grains are produced at a first stage. While straw finds are extremely rare in wetland sites, rachis fragments of naked wheats and naked barley are frequently found. A lack of straw proves that it has not been brought into the settlements and that it has not been used as a roofing material or a staple for other purposes (mats, baskets etc). For example for the early neolithic it has been suggested, that cereals were harvested high on the culm without their straw.

Concentrations, or even layers, of uncharred threshing remains of bread wheat, durum wheat or naked barley might indicate threshing places inside the village in prehistoric wetland sites. If they are lacking although carbonized threshing remains are present, this might point to threshing processes outside the settlement.

Glume bases and spikelet forks of glume wheats, sometimes mixed with small quantities of whole spikelets and grain seedcoats, are by-products from a later processing stage (van der Veen 2007, 987). From many sites it has been shown, that the dehusking was usually carried out inside the villages as a daily routine. Such a place of dehusking has probably been discovered in the neolithic settlement of Bad Buchau Torwiesen II.

References among others:

• Brombacher and Jacomet 1997
• Jacomet 1989, 92ff., 319,
• Jacomet et al. 2004, 120ff.,
• Maier 2001, 54ff.,
• Maier (in prep.)

For fibre production the stems must be rotted in ponds, ditches or on wet meadows for a couple of days, so that their wooden parts break up and the fibres are released. When the rotting is finished, the stems have to be removed from water, dried and then beaten and broken. The product of this process is the fibres, which are preserved archaeologically in the form of threads, complete fish-nets, textiles and other products. By-products are stem fragments and the stem debris (“shives”), of which sometimes large quantities are found in waterlogged sediments. If these are concentrated in particular parts of a settlement, they may indicate special processing areas.

References among others:

• Jacomet et al. 1989, 178f.,
• Jacomet et al. 2004, 124f.,
• Körber-Grohne 1967, 147ff.,
• Maier 2001, 68 ff., 199f.,
• Maier 2004, 105f.,
• Maier in prep.,
• Kenward & Hall 1995

Flax-processing with neolithic means - an experiment

Especially in neolithic wetland sites of the alpine foreland, flax was an important crop used as a food plant and as a source for fibres. In archaeological contexts products of flax, like textiles and fish-nets, have been frequently found as well as remains of the different stages of flax processing. Within the archaeobotanical project "Integrated Archaeobotanical Research IAR" at the Department of Archaeology, University of Sheffield, UK, a flax experiment has been carried out together with the "Federsee Museum" in Bad Buchau, Germany in 2008. The whole process from harvesting the plants to producing linseeds and flax fibres should be performed with neolithic means.

Pulses

Pulses can be used at different stages of ripeness. In their green, unripe stage (for example "sugarpeas") the pods as well as the seeds are fresh, soft and pulpy and of a sweet taste. As they decay rapidly, they must be eaten soon and cannot be kept for a long period. If peas are picked at a ripe stage, the pods have developed a “parchment-layer”, a sclerenchymatic endocarp which makes them rather tough, hard and inedible. In that case the pods have to be removed from the seeds and are probably discarded as waste material or used as animal fodder. The ripe seeds are dry and hard and can be stored for longer. The pods found in the archaeological samples prove that the pulses were harvested at a ripe stage, when the sclerenchymatic endocarp had already been developed, and that these pulses may have been stored.

References among others:

• Kenward & Hall 1995, fig. 191, p. 684,
• Körber-Grohne 1967, 174ff., pl. 39-41,
• Maier 2001, 73f.,
• Maier 2004, 85.

Crab apple

How crab apples were processed in prehistoric times is shown by accumulations of charred apples found at waterlogged sites. Nearly all these apples have been cut in half and the skin of the fruits show that they must have been dried before charring. Probably these fruits were collected as a winter supply of Vitamin C and were destroyed accidentally during their preservation process.

References among others:

• Gassner et al. 1989
• Jacomet et al. 1989, 199f.
• Kenward & Hall 1995, fig 191, p. 682
• Maier 2001,
• Maier 2004

Mistletoe

Mistletoe has always been used as a ritual and magical plant as well as for medical purposes, but these uses can hardly be proved in the archaeobotanical material. However thick layers of epidermis fragments found at waterlogged sites, and the occurrence of remains in dung pellets show that at least in neolithic times the plant must have been used as a winter fodder for animals. The berries of mistletoe can also be used as a glue, for example to prepare glue traps for birds.

References among others:

• Kühn, Hadorn 2004
• Maier 2001, 135ff., 208
• Zibulski 2004

References

• Dickson, J.H. & Dickson, C.A. (1979). Flour or bread in a Roman military ditch at Bearsden, Scotland. Antiquity 53, 47-51.
• Dickson, C. (1989). The Roman army diet in Britain and Germany. In: Körber-Grohne, U. und Küster, H. (Eds.), Archäobotanik. Symposium der Universität Hohenheim (Stuttgart) vom 11.-16. Juli 1988. dissertationes Botanicae 133: 135-154.
• Gassner, G.,Hohmann, B., Deutschmann, F. (1989). Mikroskopische Untersuchung pflanzlicher Lebensmittel. 414 p. Stuttgart/New York.
• Greig, J. R. A. (1981). The investigation of a medieval barrel-latrine from Worcester. Journal of Archaeological Science 8. 265-82.
• Huntley, J., J. Hillam (2000). Environmental evidence. In: K. Buxton, C. Howard-Davis: Bremetenacum. Excavations at roman Ribchester 1980, 1989-1990. Lancaster Imprints Series Number 9, p. 349-374.
• Jacomet, S., Brombacher, Ch., Dick, M. (1989). Archaeobotanik am Zuerichsee. Berichte der Züricher Denkmalpflege, Monographien 7. Zürich 348 p.
• Jacomet, S., Leuzinger, U., Schibler, J. (2004). Die jungsteinzeitliche Seeufersiedlung Arbon/Bleiche 3. Umwelt und Wirtschaft. Archäologie im Thurgau, Band 12. Veröffentlichungen des Amtes für Archäologie des Kantons Thurgau, 458 S.
• Kenward, H.K., Hall, A.R. (1995). Biological Evidence from Anglo-Scandinavian Deposits at 16-22 Coppergate. The Archaeology of York. Vol. 14: The Past Environment of York, Fascicule 7, p. 435-797.
• Körber-Grohne, U. (1967). Geobotanische Untersuchungen auf der Feddersen Wierde. In: Haarnagel, W. (ed.), Feddersen Wierde, Band I, Römisch-Germanische Kommission des Deutschen Archäologischen Instituts zu Frankfurt am Main und Niedersächsisches Landesinstitut für Marschen- und Wurtenforschung in Wilhelmshaven. Wiesbaden, 355 p.
• Kühn, M., Hadorn, Ph. (2004). Pflanzliche Makro- und Mikroreste aus Dung von Wiederkäuern. In: Jacomet, S. et al.: Die jungsteinzeitliche Seeufersiedlung Arbon/Bleiche 3. Umwelt und Wirtschaft. Archäologie im Thurgau, Band 12. Veröffentlichungen des Amtes für Archäologie des Kantons Thurgau, 327-350.
• Maier, S. (1988). Botanische Untersuchung römerzeitlicher Pflanzenreste aus dem Brunnen der römischen Zivilsiedlung Köngen (Landkreis Esslingen). Forschungen und Berichte zur Vor- und Frühgeschichte in Baden-Württemberg 31, 291-324.
• Maier, U. (2001). Archäobotanische Untersuchungen in der neolithischen Ufersiedlung Hornstaad-Hörnle I A am Bodensee. Siedlungsarchäologie im Alpenvorland VI. Foschungen und Berichte zur Vor- und Frühgeschichte in Baden-Württemberg 74, 9-384. Stuttgart.
• Maier, U. (2004). Archäobotanische Untersuchungen in jung- und endneolithischen Moorsiedlungen am Federsee. In: Ökonomischer und ökologischer Wandel am vorgeschichtlichen Federsee. Hemmenhofener Skripte 5, 71-159.
• Maier, U. (in prep.). Archäobotanische Flächenuntersuchungen in der Station Torwiesen II in Bad Buchau (Kr. Biberach).
• Zibulski, P. (2004). Zweige und Knospen. In: Jacomet, S. et al. : Die jungsteinzeitliche Seeufersiedlung Arbon/Bleiche 3. Umwelt und Wirtschaft. Archäologie im Thurgau, Band 12. Veröffentlichungen des Amtes für Archäologie des Kantons Thurgau, 313-326.