Cupressaceae: A plant family of the order Pinales, class Pinopsida, division Coniferophyta (conifers). They are mainly resinous, aromatic evergreen trees.Juniperus: A plant genus of the family CUPRESSACEAE. The species are slow growing coniferous evergreen trees or shrubs.Thuja: A plant genus of the family CUPRESSACEAE.Taxodium: A plant genus of the family TAXODIACEAE. Members contain taxodione and taxodone, which are diterpenoid quinone methide tumor inhibitors.Cupressus: A plant genus of the family CUPRESSACEAE. Cypress ordinarily refers to this but also forms part of the name of plants in other genera.Coniferophyta: A plant division of GYMNOSPERMS consisting of cone-bearing trees and shrubs.Chamaecyparis: A plant genus of the family CUPRESSACEAE which should not be confused with other cedar and cypress trees of THUJA or CUPRESSUS genera.Cryptomeria: A plant genus of the family TAXODIACEAE. Its POLLEN is one of the major ALLERGENS.Pollen: The fertilizing element of plants that contains the male GAMETOPHYTES.Ambrosia: A plant genus of the family ASTERACEAE. The POLLEN is one cause of HAYFEVER.Betula: A plant genus of the family BETULACEAE. The tree has smooth, resinous, varicolored or white bark, marked by horizontal pores (lenticels), which usually peels horizontally in thin sheets.Fossils: Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.