Vitex sp.

Niccolini, Gabriele, Martinetto, Edoardo, Lanini, Benedetta, Menichetti, Elena, Fusco, Fabio, Hakobyan, Elen & Bertini, Adele, 2022, Late Messinian Flora From The Post-Evaporitic Deposits Of The Piedmont Basin (Northwest Italy), Fossil Imprint 78 (1), pp. 189-216 : 202-203

Vitex sp.

Pl. 3, Fig. 4

M a t e r i a l. A leaf from the Sioneri locality,

MCEA-P05042.

R e m a r k s. The fossil leaf is chartaceous, palmately compound with 5 leaflets of different dimensions (Pl. 3, Fig. 4a). The leaflets are broadly lanceolate, with entire margins, attenuate apex and either very short or missing petiolules (leaflets sessile). Secondary veins relatively densely spaced and gradually becoming thinner towards the margin, thus hampering perception of a brochidodromous pattern. Tertiary veins densely spaced, slightly oblique and sometimes percurrent (Pl. 3, Fig. 4b).

A morphology very similar to that shown by the Sioneri leaf was first noticed in extant shrubs of V. agnus-castus L. cultivated in the public gardens in the town of Turin. Later, hundreds of images of this and other extant species of Vitex were examined in digitized herbarium sheets available through the following portals: JStor Global Plants (https:// plants.jstor.org), iDigBio (https://www.idigbio.org), Plants of the World Online (https://powo.science.kew.org), RecolNat (https://www. recolnat.org). Several reliably identified specimens confirm that the combination of characters found in the fossil leaf occurs in extant leaves of V. agnus-castus , even though the leaflets of this species usually bear distinct petiolules and tend to be narrowly lanceolate. Only the image of a plant cultivated in Denmark (Botanisk Have Aarhus, photo Egon Krogsgaard, 18 October 2020: https://powo. science.kew.org), labeled as V. agnus-castus , corresponds 100% with the Sioneri leaf due to the sessile and broadly lanceolate leaflets. However, other species of Vitex bear more regularly leaves with these characters, such as V. rehmannii GÜRKE of South Africa (Pl. 3, Fig. 5). The pattern of tertiary veins of this last species corresponds well with both the fossil (Pl. 3, Fig. 4b) and V. agnus-castus (Pl. 3, Fig. 6).

The characters shared by the fossil leaf and the leaves of the two above-mentioned extant species seem to be sufficient to suggest assignment of the fossil leaf to the genus Vitex , but a possible determination at species level would require further research.