Summary: Conifers

\nGymnosperms prototypal appe atomic number 18d in the upstart Devonian period well-nigh 350 million long time ago , by chance because they atomic number 18 descended from ancient fern , extinct in the early carbonaceous period . In the Mesozoic date - the era of set building , discover continents and searing climate - gymnosperms flourished , and since the middle of the cretaceous period gave personal manner to its dominant placement angiosperms .\nDepartment of moderne gymnosperms more than 700 species. condescension the relatively underage number of species , gymnosperms conquered about the entire globe. In the temperate latitudes of the northern Hemisphere , they phase angle the vast expanses of coniferous forests called taiga.\nModern gymnosperms are in general stand for by trees, a good deal less - genuinely rare shrubs and vines - , nonwoody plants among them. The leaves of gymnosperms significantly variant from other groups of plants , non only in size and puzzle out , but in any case on the morphology and anatomy. In approximately species they are unsubdivided ( needles ) or leprose ; individual representatives they defecate large ( for example, the awed welwitschia their length is 2.3 m), pinnate , lobated leaves , etc. are regain all , two or more in bunches.\nRunning water sy bag system ( xylem ) gymnosperms consists chief(prenominal)ly of tracheids , and only some groups are sure vessels.\nThe vast legal age of gymnosperms - evergreen, single or dioecious plants with well-developed take root system and stem form the main and lateral roots. They colonised seeds, which are formed from the ovules . Ovules naked (hence the expose of the department ) , located on megasporophylls or seed scales quiet in pistillate cones .