Дефиниција: A taxon is Extinct when there is no reasonable doubt that the last individual has died. A \r\ntaxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, \r\nat appropriate times (diurnal, seasonal, annual), throughout its historic range have failed \r\nto record an individual. Surveys should be over a time frame appropriate to the taxon’s \r\nlife cycle and life form.
Дефиниција: An alpine condition is an environmental condition in which the monthly mean temperature is less than 10 degrees Celsius and which occurs at altitudes above the tree line and below the snowline.
Дефиниција: The important feature of homospory is the four fold division involved in spore production, this takes the form of either a tetrahedra which gives a trilete (Y shaped scar) spore or a tetragon which gives a monolete (single linear scar) spore.
Дефиниција: The institution that holds a type specimen for a given species. The recommended best practice is to use the identifier in a collections registry such as the Biodiversity Collections Index (http://www.biodiversitycollectionsindex.org/).