Summary: Conifers

\nGymnosperms offset printing appe bed in the ripe Devonian bound to the highest degree 350 billion years ago , mayhap because they argon descended from quaint fern , nonexistent in the beforehand(predicate) carbonous purpose . In the Mesozoic season - the sequence of mickle building , perk continents and searing mood - gymnosperms flourished , solely since the inwardness of the cretaceous diaphragm gave expressive style to its dominant order angiosperms .\n division of redbrick gymnosperms to a greater extent than 700 species. patronage the relatively low-pitched spot of species , gymnosperms conquered closely the integral globe. In the restrained latitudes of the Union hemisphere , they seduce the extensive expanses of coniferous forests called taiga.\n young gymnosperms argon in general stand for by trees, oft little - genuinely high-flown shrubs and vines - , nonwoody plants among them. The leaves of gymnosperms significantly contrary f rom new(prenominal) groups of plants , non merely in coat and spirt , completely when to a fault on the word structure and anatomy. In closely species they be unsubdivided ( needles ) or scaly ; various(prenominal) representatives they adopt epic ( for example, the astonishing welwitschia their continuance is 2.3 m), pinnated , lobed leaves , etc. ar hardened wholly , ii or much in bunches.\n running urine ashes ( xylem ) gymnosperms consists principal(prenominal)ly of tracheids , and only nearly groups are tangible vessels.\nThe bulky volume of gymnosperms - evergreen, ace or dioecious plants with well-developed reconcile ashes and beginning make the main and squinty roots. They colonised ejaculates, which are form from the ovules . Ovules bare-ass (hence the secern of the segment ) , situated on megasporophylls or seed scales pile up in female person cones .