LYCOS RETRIEVER 
Pollen
built 649 days ago
Pollen grains are an outrageous invention of the seed plants, which first appeared over 300 million years ago. Pollen frees the seed plants from dependence on standing water for [F]ertilization, which is needed by the spore-reproducing plants like ferns. The distinction is similar to the difference between amphibians vs. reptiles. Pollen is produced in the male organs of the flowers - anthers. Pollination occurs when pollen is transfered from the anthers to the female organs by wind (anemophyly) or by animals (zoophyly). If the female stigma is receptive to a pollen grain, the pollen produces a pollen tube, which grows through the female tissue to the egg, where fertilization takes place by the sperm nucleus.
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Pollen forecasts are calculated using gathered information, as well as local vegetation distribution, weather patterns and weather forecasts. The pollen forecast is usually given as LOW, MODERATE, HIGH or VERY HIGH. In the case of grass, LOW is less than 30 grains per cubic metre of air, MODERATE 30 to 49, HIGH 50 to 149 and VERY HIGH 150 or more.
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Pollen may have problems with some multiple screen setups, and performance is likely to be poor since a separate copy is run for each screen. You may prefer to have Pollen render only to your main screen, leaving all other screens blank; hence the checkbox in the configuration dialog. If you continue to have multiple screen problems even with this preference checked, please send in a bug report.
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Pollen grains may have furrows, the orientation of which classify the pollen as colpate or sulcate. The number of furrows or pores helps classify the flowering plants, with eudicots having three colpi (tricolpate), and other groups having one sulcus.[1] [2]
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Pollen grains which are washed or blown into lakes can accumulate in sediments and provide a record of past vegetation. Different types of pollen in lake sediments reflect the vegetation that was present around the lake, and therefore the climate conditions favorable for that vegetation. The NOAA Paleoclimatology Program distributes the product of various collaborative efforts to collect and organize pollen records from around the globe. These data include the pollen counts and related information, as well as several different derived data sets. Data archived here were last updated in February 2005. Data contributed since March 2005 are available from PaleoScienceData.net
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Pollen's sporopolenin outer sheath affords it some resistance to the rigours of the fossilisation process that destroy weaker objects; it is ... produced in huge quantities. As such, there is an extensive fossil record of pollen grains, often disassociated from their parent plant. The discipline of palynology is devoted to the study of pollen, which can be used both for biostratigraphy and to gain information about the abundance and variety of plants alive - which can itself yield important information about paolæoclimates. Pollen is first found in the fossil record in the late Devonian period
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Pollen