Cupressus from a palynological point of view

Together with Olea europaea (olive tree) and Vitis vinifera (grapevine), Cupressus (cypress) is an emblematic component of the Tuscan landscape. It characterizes the skyline of the hills, lines the roads, forms small thickets in squares and around farmhouses and shadows the graves in cemeteries providing a note of dark green in contrast to the silver green of the olive trees. On the other hand, Cupressus pollen is one of the main causes of the winter allergic respiratory diseases in Tuscany as in many parts of the world, owing to its wide distribution area which has been enormously enlarged by cultivations. The typical cypress species in Tuscany is Cupressus sempervirens L. The pollen of Cupressus is almost spheroidal with an unevenly granular surface. Hydration provokes the sudden swelling of the intine, with the consequent rupture of the thin exine layer. In palaeo- and archaeopalynological analysis, after the routine chemical treatments, the only visible portion of the grains is just the thin exine layer, which generally appears crumpled or fragmented and sometimes it is difficult to detect. Consequently, although these plants produce a huge amount of pollen grains, relative low quantities of Cupressus and Cupressaceae pollen are often recorded in ancient sediments.