Pollen to pollen is called pollinosis, and allergy specifically to grass pollen is called hay fever. Generally, pollens that cause allergies are those of anemophilous plants (pollen is dispersed by air currents.) Such plants produce large quantities of lightweight pollen (because wind dispersal is random and the likelihood of one pollen grain landing on another flower is small), which can be carried for great distances and are easily inhaled, bringing it into contact with the sensitive nasal passages. Pollen allergies are common in polar and temperate climate zones, where production of pollen is seasonal. In the tropics pollen production varies less
Spore print print is pure white or, rather, very slightly pigmented. The mushroom is left for several hours, often overnight, in this manner. Some guides advise using a moisture-resistant enclosure, like a glass or jar, to contain the mushroom during printing. If the mushroom is to be preserved, a small hole can be made in the spore print paper rather than cutting the stipe. When the mushroom is removed, the color of the spores should be visible. Mycologists often use glass slides, which allow for quick examination of spores under a microscope. A mushroom cannot be identified from its spore print alone;