title: Plant pollination of a low intensity as causal agent of seasonal allergy
abstract: Many well-known plants such as a birch, alder, hazel, oak, grasses, ragweed, sa­geb­rush, etc. produce a huge amount of the allergenic pollen. Some pollen types represented in the ambient air with low concentrations only are able to provoke the hay fever symptoms. These are particles migrating over long distances through the atmosphere, pollen of entomophilic and rare plants of the particular area. 16 aeropalynological categories of arboreal flora emitting small number of pollen grains into the 
journal: Studia Biologica