Buried, viable seeds in two California bunchgrass sites and their bearing on the definition of a flora

摘要: A complete description of a plant community must include the buried viable seeds in soil. The plants occurring this form are part flora, which helps to determine community, even though they not readily evident. importance defining an ecosystem's flora is reviewed. When soil's seed population used help various problems arise since perennial reproduce much less abundantly by than do annuals, laboratory germination conditions probably suit all species, and distributed at random so sampling made difficult. In investigation two grazed ungrazed California bunchgrass sites poor correspondence between vegetation soil populations was found. Numbers were 8000 12,000 per m2. Figures order or magnitude general periodical literature describes factors influence them qualitatively quantitatively kinds arable, mesic pastured mown, steppe, forest communities. Not only evident above ground stand ecosystem includes that vegetation, also disseminules This paper records determination numbers stands ofStipa pulchra, eastern foothills central Coast Ranges California. Such variable from year year, over climatic cycle years, successionally (i.e.), it seral therefore changes with time, other habitat being constant (Heady 1958). By no means species can occur period several years one time. We have attempted use content buried, as measure potential flora.