Pollen grains identification under light microscopy is based on morphological characteristics such as shape, size, apertures and ornementation. The combination of these characteristics makes some pollen grains easily identifiable, showing low confusion possibility. But there are also pollen grains sharing several common characteristics that make identification difficult.
Once decided the four A.S.T.H.M.A. pollen types, and begun the transfer of palynological information for developing the semi-automatic system for pollen recognition, it appeared very clear the need to include in the study the pollen types similar, in order to avoid confusions and overestimates.
In order to decide which pollen types are similar to the main A.S.T.H.M.A. pollens that will be included in the project, two main aspects were taken into consideration: the abundance of the similar pollen in the atmosphere and the coincidence in the pollination periods of similar pollen types.
In addition to the main A.S.T.H.M.A. pollens (Cupressaceae, Olea, Parietaria and Poaceae), the other pollen grains included in the A.S.T.H.M.A. project are: Brassicaceae, Broussonetia, Celtis, Coriaria, Fraxinus, Ligustrum, Phillyrea, Populus, Salix and Morus. In a second step, other pollen types will be considered: Alnus, Ambrosia, Artemesia, Betula, Cannabis, Carpinus- Ostrya, Cariophyllaceae, Castanea, Casuarina, Chenopodiaceae-Amaranthaceae, Corylus, Palmae, Pinus, Plantago, Platanus, Quercus, Rumex, Ulmus.
If you click on the pollen types (first row), you can see some examples of images of the type and its similars (listed in column).
In a second step, we are trying to identify other frequent and abundant pollen types (to see some examples):
Alnus, Ambrosia, Artemesia, Betula, Cannabis, Carpinus- Ostrya, Cariophyllaceae, Castanea, Casuarina, Chenopodiaceae-Amaranthaceae, Corylus, Palmae, Pinus, Plantago, Platanus, Quercus, Rumex, Ulmus.