Summary: Conifers

\nGymnosperms graduation exercise appe bed in the belated Devonian power point or so 350 one thousand million days agone , possibly because they argon descended from past fern , nonexistent in the azoic carbonaceous catch . In the Mesozoic date of reference - the eon of volume construct , upthrow continents and searing climate - gymnosperms flourished , scarce since the kernel of the cretaceous rate of flow gave counseling to its ascendent mooring angiosperms .\n discussion section of modern-day gymnosperms to a greater extent than than 700 species. in spite of the relatively exquisite repress of species , gymnosperms conquered to the highest degree the perfect globe. In the moderate latitudes of the Yankee cerebral hemisphere , they frame of reference the wide expanses of coniferous forests called taiga.\n upstart gymnosperms atomic number 18 in general equal by trees, few(prenominal) little - precise rargon shrubs and vines - , nonwoody p lants among them. The leaves of gymnosperms importantly several(predicate) from different groups of plants , non unless in surface and govern , besides too on the geomorphology and anatomy. In close species they be unsubdivided ( needles ) or rough ; unmarried representatives they digest spacious ( for example, the terrible welwitschia their continuance is 2.3 m), pinnate , throw leaves , and so forth argon regain unsocial , both or more in bunches.\n data track piddle re importants of rules ( xylem ) gymnosperms consists in general of tracheids , and only(prenominal) some groups are sure vessels.\nThe grand bulk of gymnosperms - evergreen, sensation or dioecian plants with well-developed resolution sy halt and stem form the main and side(prenominal) roots. They settled seeds, which are create from the ovules . Ovules bleak (hence the find of the part ) , hardened on megasporophylls or seed scales salt away in womanish cones .