Fig 1.
Location of Lake Zürich within the Alpine region (above) and plan of Parkhaus Opéra and other prehistoric pile dwellings around Lake Zürich (below). Image: Office for Urbanism Zürich / N. Bleicher.
Fig 2.
Section of the excavation at Parkhaus Opéra. Positions of find no. 2010.012.2285.3 = 2285 and find no. 2010.012.2907.5 = 2907 in Layer 13 are indicated in relation to buildings and the charcoal layer of a catastrophic fire event. Image: Office for Urbanism Zürich / N. Bleicher.
Fig 3.
Illustration of the state of preservation of organic matter in the cultural layer, in direct vicinity of find no. 2907. Wooden remains are visible as light-brown objects. Arrows indicate a) Rope fragments and a b) Bracket fungus fragment. Image: Office for Urbanism Zürich / N. Bleicher.
Fig 4.
Overview of the two analysed bread-like objects.
Possible upper surface of a) Find no. 2285 and b) Find no. 2907. Centimetre scale. Image: ÖAI-ÖAW, VIAS / A. G. Heiss.
Table 1.
Basic description of the two bread-like objects from the excavation at Parkhaus Opéra.
Fig 5.
Diagnostic cereal tissue types as visible in plane sections.
Species: a) Barley (Hordeum vulgare), and b) Bread wheat (Triticum aestivum). Tissue types: 1) epidermis at the apex (left) and in the middle of the grain (right), 2) Hypodermis, 3) Cross cells, 4) Tubular cells, 5) Testa, 6) Perisperm, 7) Aleurone. Applied diagnostic features: 3a) Thin-walled cross cell walls in barley, often in a double layer (the latter not visible under SEM), and 3b) Thick-walled, regularly and conspicuously pitted cross cells in wheat species ([41], modified).
Fig 6.
Diagnostic cereal tissue types as visible in cross sections.
Species: a) Barley (Hordeum vulgare), and b) Bread wheat (Triticum aestivum). Grain parts and tissue types: 1) glume, 2) Pericarp and seed layers (corresponding to Fig 5, numbers 1 to 6), 3) aleurone tissue, 4) endosperm. Applied diagnostic features: 3a) Double to triple layer of aleurone in Hordeum, in contrast to 3b) Typically single layers as in Triticum and all other Old World cereal crops ([41], modified).
Fig 7.
B/W images used as raw data for image analysis in a) Find no. 2285, and b) Find no. 2907. Centimetre scale. Image: ÖAW-ÖAI, VIAS / A. G. Heiss.
Fig 8.
Overview of a fractured face of find no. 2285.
Arrows indicate grains identifiable as barley (Hordeum vulgare). Scale bar length: 1 cm. Image: ÖAW-ÖAI, VIAS / A. G. Heiss.
Fig 9.
SEM images from find no. 2285.
Arrows indicate cross cell patches. a-c) Overview images, d) Detailed view of c, showing thin-walled cross cells as found in barley (Hordeum vulgare).
Fig 10.
Overview of a fractured face of find no. 2907.
The arrow indicates a grain identifiable as most likely barley (cf. Hordeum vulgare). Scale bar length: 1 cm. Image: ÖAW-ÖAI, VIAS / A. G. Heiss.
Fig 11.
SEM images from find no. 2907.
Arrows indicate regions of interest. a) Cross cells patch, covered by a patch of aleurone cells. b) Magnification of a, showing thick-walled and pitted cross cells as found in wheat (Triticum sp.). c) Cross cells embedded in the matrix. d) Magnification of c, showing the thick-walled and pitted cross cells of the Triticum sp. type. e) Portion of a cereal grain showing single-layered aleurone. f) Cereal grain showing several pericarp layers, from aleurone cells on the left to cross cells on the right hand side. Image: ÖAW-ÖAI, VIAS / A. G. Heiss.
Fig 12.
SEM image of the celery (cf. Apium graveolens) fruit.
a) Embedded in the matrix of find no. 2907, b) In magnified view. Image: ÖAW-ÖAI, VIAS / A. G. Heiss.
Fig 13.
Experimentally charred schizocarp of celery (Apium graveolens).
Scale bar length: 100 μm. Image: ÖAW-ÖAI / A. G. Heiss.
Fig 14.
Histogram of the recorded maximum dimensions of components (N = 223) in find no. 2285.
Y axis: number of occurrences, Y axis: size class in micrometres (in 100 μm steps). Grouping is according to grain sizes of modern grain products: a) Flour and dunst (smaller than 300 μm), b) Semolina (300–1000 μm), and c) Grist (larger than 1000 μm). Raw data is given in S1 Table.
Fig 15.
Histogram of the measured cavities (N = 2,368) in find no. 2907.
Y axis: number of occurrences, Y axis: size class in micrometres (in 100 μm steps). Raw data is given in S2 Table.
Fig 16.
Histogram of the recorded maximum dimensions of components (N = 287) in find no. 2907.
Y axis: number of occurrences, Y axis: size class in micrometres (in 100 μm steps). Grouping according to grain sizes of modern grain products: a) Flour and dunst (smaller than 300 μm), b) Semolina (300–1000 μm), and c) Grist (larger than 1000 μm). For raw data see S3 Table.
Fig 17.
Histogram of the measured cavities (N = 639) in find no. 2907.
Y axis: number of occurrences, Y axis: size class in micrometres (in 100 μm steps). Raw data is given in S4 Table.
Fig 18.
Grain size measurements of both finds.
Symbols: °: extremal values, *: outliers. For raw data, see S1 and S3 Tables.
Fig 19.
Cavity measurements of both finds.
Symbols: °: extremal values, *: outliers. For raw data, see S2 and S4 Tables.