Detecting ‘flavour’ in past cuisines: phytolith reference collections for Mediterranean herbs.

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• January 28, 2026
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An article by Carlos G. Santiago-Marrero, Cristina N. Patús, Costanza Dal Cin d’Agata, Teresa Garnatje and Juan José García-Granero

Herb use in the Mediterranean Antiquity

Herbs, aromatic plants belonging to specific families, have had a long and continuous history in many human societies. In the Mediterranean region, numerous factors have rendered herb use particularly culturally significant. They have been added in recipes, used in the production of aromatic oils and utilized as pharmaceutical ingredients (Fappas, 2009; Valamoti, 2013; Cultural and Technological Institute ΕΤΒΑ & Biological Association of Cyprus, 1997). Their deep connection to human practices continues to manifest itself today, as people persist on using them, often not following a rationalized thought process, but simply mirroring long-standing regional traditions (Kourti, 2024).

Why include phytoliths?

This plant category, although somewhat visible in the archaeobotanical/textual record is particularly hard to decipher; for the most part, archaeobotanical studies in the Mediterranean region have been based on macroscopic remains, rendering the leaves, the USOs and the flowering parts of the plant virtually invisible. The presence of seeds, although informative, can not be directly linked to their use as aromatic/pharmaceutical ingredients. It is important to note that most of these plants grow naturally in the wider environment of most settlements, so it is not strange when they are interpreted as weeds or dung components (for example, see Valamoti, 2004).

This study, aiming to create a Mediterranean herb reference collection for phytoliths, is the first step towards recovering this, until now, inaccessible information. Apart from their presence in leaves, which could make them the ideal proxy for some of these plants, phytolith analysis can be directly linked to food preparation contexts, thus facilitating the interpretation.

Methodology: a more precise approach to plant sampling

This reference collection analyzed 39 plant species and obtained a total of 62 samples. Not only the plant species selection was based on historical and ethnographical sources, but also the plant part sampling: it was decided to sample the parts of known culinary value, varying between different species.

The plants were collected from botanical gardens and parks in Crete and Barcelona, and they were cleaned, ashed at 500°C and treated with 5% hydrochloric acid. All phytoliths present on 25% of the slide (5 tracks) were counted and described following the ICPN 2.0 and anatomical names/nomina conservada in cases where the morphotype observed did not fit within the ICPN standard morphotypes.

Key results

Phytoliths were observed in 32 species and 42 modern reference samples. The concentration was generally low, and some variability was observed between different plant parts or even different accessions of the same plant part. Out of the 42 samples, 9 were considered virtually sterile, since less than 10 single phytoliths were observed. Therefore, 33 samples and 24 species were considered when discussing the results.

In total, 13 main phytolith morphotypes were observed, which were then subdivided into 51 sub-morphotypes based on secondary features (ornamentation, texture etc.). The main morphotypes were presented in groups, according to their physiological functions:

• Acicular, Acute, Hair base and Trichome. This group was the most often observed (25 samples from 20 species). Some of the morphotypes present in it could potentially hold taxonomic value.
• Amoeboid. This group was observed only in two of the Artemisia sp. species, with unknown taxonomic value.
• Elongate. This group represents one morphotype (Elongate Entire) present in one species (Mentha x piperita L.), with no apparent taxonomic value.
• Oblong, Polygonal and Tabular. Third most observed, this group was present in 21 samples from 17 species. Some silica skeletons with potential taxonomic value were found in two Mentha L. spp. species.
• Polyhedral. This group, represented by two sub-morphotypes, did not hold any taxonomic value, although present in some samples.
• Spheroid. The morphotype representing this group, Spheroid Psilate, was observed in some Mentha L. spp. samples, but doesn’t hold any taxonomic value.
• Stoma. Two morphotypes (circular and ovate) of Stomata were observed in 13 samples of different species. Since there are no apparent differences between them, it is considered that they do not have taxonomic value.
• Tracheary. This group is the second most often present in the collection (24 samples from 16 species). It was represented by two similar sub-morphotypes, with their only difference being the length. Their taxonomic value is low due to their presence in numerous different species.

Phytolith production was low in Mediterranean herbs, in comparison to other angiosperms studied in regionally relevant reference collections.

The highest phytolith production was documented in the leaves of Laurus nobilis, Reichardia picroides (L.) Roth and Santolina chamaecyparissus L.

The species presenting the highest sub-morphotype diversity were all the mint ones (Mentha L. spp.) and Spanish oregano (Satureja thymbra L.). The rest of the species studied produced about 1 to 5 morphotypes.

Fig. 1 : Morphotypes with taxonomic value. A) Polygonal striate, articulated from Mentha spicata L. B) Tabular sinuate, articulated from Mentha spicata L (TAB_SIN_4). C) Tabular sinuate, articulated from Mentha x piperita L. (TAB_SIN_2). D) Tabular sinuate, articulated from Mentha x piperita L. (TAB_SIN_3). E) Acicular compound from Foeniculum vulgare Mill. F) Trichome stellate from Lavandula stoechas L.

Six of the studied species presented phytoliths with taxonomic potential, and it’s important to note that only one of them (Lavandula stoechas L.) presented a morphotype that seems to be species-specific (fig. 1F). The rest of the morphotypes shown in the figures were present in several of the species studied, which, could allow for an identification on the family or genus level.

Factors to consider and forthcoming steps

The way this reference collection was constructed allows for some interesting comparisons. Firstly, not only the most phytolith-abundant samples came from the leaves of the aforementioned species, but when having the opportunity to examine both flowers/inflorescence parts and leaves from the same species, the leaves produced higher phytolith counts. Secondly, the fact that the plants came from different parts of the Mediterranean was considered, and in some cases the difference was clear, with some species showing higher counts in the East or the West.

This reference collection constitutes the first step towards the exploration of this plant category. Therefore, it is highly significant that it includes a high number of species. Considering this, the plant part selection is a time and resource saving element of this study that greatly benefits it. Nevertheless, it remains that, our modern ideas of which plant parts are of culinary value may not be entirely reflected in prehistorical contexts.

Edaphic conditions and general taphonomical and climatological factors can greatly affect not only the production, but also the level of wear of the existing silica skeletons (e.g. Chrysovergi, 2025). This is why several reference collections opt for the time-consuming gathering of species in areas where they are organically present. In these areas the growing conditions may be largely unknown but are considered somewhat similar to those of the prehistoric specimens (Rousou and Kouka, 2024).

Lastly, the study of phytoliths alone is not enough to assess the use of this very variably used plant category. Apart from the necessary aid from residue analyses, this referential could be enriched with other micro-proxies that may help identify some plant parts that are not as present in the phytolith assemblage (i.e. Cagnato et al., 2021).

To read the entire paper : https://doi.org/10.1016/j.revpalbo.2025.105345

Additional references

Cagnato, C., Hamon, C., Salavert, A., & Elliott, M. (2021). Developing a Reference Collection for Starch Grain Analysis in Early Neolithic Western Temperate Europe. Open Archaeology, 7(1), 1035–1053. https://doi.org/10.1515/opar-2020-0186

Chrysovergi, E. (2025). Experimental approaches on the taphonomy of archaeobotanical micro-remains of ancient foods [Master’s Dissertation]. Aristotle University of Thessaloniki.

Fappas, I. (2009). Τα αρωματικά έλαια και οι πρακτικές χρήσης τους στη Μυκηναϊκή Ελλάδα και την Ανατολική Μεσόγειο (14ος‐13ος αι. π.Χ.) [PhD Thesis]. Aristotle University of Thessaloniki.

Kourti, E. S. (2024). Εθνογραφικές και Πειραματικές Προσεγγίσεις στην Διερεύνηση της Εκμετάλλευσης των Φυτικών Πηγών στην Βόρεια Ελλάδα κατά τη Νεολιθική Περίοδο (6η—4η χιλιετία π.Χ.). Ρητίνη, ο Τόπος Και Οι Άνθρωποι: Από Την Προϊστορική Περίοδο Μέχρι Σήμερα, Barbounakis, Thessaloniki: 81–100.

Rousou, M., & Kouka, O. (2024). Constitution des collections de référence de matériel botanique moderne à Chypre: Méthodes, perspectives et apport à la recherche archéologique. Cahiers Du Centre d’Études Chypriotes, 54, 209–237. https://doi.org/10.4000/12ls5

Valamoti, S. M. (2004). Plants and People in Late Neolithic and Early Bronze Age Northern Greece: An archaeobotanical investigation. Archaeopress.

Valamoti, S. M. (2013). Healing with Plants in Prehistoric Northern Greece: A Contribution from Archaeobotany. Offa, 69/70, 479–494.

Cultural and Technological Institute ΕΤΒΑ & Biological Association of Cyprus (eds.). (1997). Φαρμακευτικά και αρωματικά φυτά: Παραδοσιακές χρήσεις και δυνατότητες αξιοποίησής τους: Ζ΄τριήμερο εργασίας, Κύπρος, Παραλίμνι 21-25 Μαρτίου 1997. Πολιτιστικό Τεχνολογικό Ίδρυμα ΕΤΒΑ.