Pollen tube by recognition and hydration of the pollen that allows for germination of the tube and ultimate growth. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube. There is competition in this step as many pollen grains may compete to reach the egg. The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. Some plants have mechanisms in place to prevent
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;