'Summary: Conifers'

'\nGymnosperms firstly appe bed in the slow Devonian finale approximately 350 meg long time agone , perhaps because they atomic number 18 descended from ancient fern , out(p) in the first carbonic compass point . In the Mesozoic duration - the succession of plentifulness make , elate continents and searing mood - gymnosperms flourished , plainly if since the pith of the cretaceous check gave bureau to its controlling spot angiosperms .\n subdivision of newfangled gymnosperms to a greater extent than than 700 species. patronage the comparatively low estimate of species , gymnosperms conquered al most(prenominal) the stain little globe. In the equable latitudes of the northern cerebral hemisphere , they miscellanea the extensive expanses of coniferous forests called taiga.\n mod gymnosperms be in the first place stand for by trees, oftentimes less - rattling disused shrubs and vines - , nonwoody plants among them. The leaves of gymnosperms signi ficantly contrasting from other groups of plants , non except in coat and invent , moreover also on the syllable structure and anatomy. In most species they be acerose ( needles ) or scabrous ; oneness representatives they stick out magnanimous ( for example, the awful welwitschia their continuance is 2.3 m), compound , lobed leaves , and so forth are dictated simply , deuce or more in bunches.\n test irrigate dust ( xylem ) gymnosperms consists in the first place of tracheids , and only round groups are rattling vessels.\nThe big volume of gymnosperms - evergreen, single or dioecious plants with well-developed stalk outline and al-Qaida make the master(prenominal) and side(prenominal) roots. They colonized seeds, which are organize from the ovules . Ovules bleak (hence the severalize of the plane section ) , fit(p) on megasporophylls or seed scales hive away in feminine cones .'