Evolutionary history of plants foliage consisted of fern-like fronds, although they were not closely related to ferns. The oldest fossil evidence of seed plants is of Late Devonian age, and they appear to have evolved out of an earlier group known as the progymnosperms. These early seed plants ranged from trees to small, rambling shrubs; like most early progymnosperms, they were woody plants with fern-like foliage. They all bore ovules, but no cones, fruit or similar. While it is difficult to track the early evolution of seeds, the lineage of the seed ferns may be traced from the simple trimerophytes through homosporous Aneurophytes. This
Economics of nuclear power plants due to significantly lower labour rates. A 2008 study by former utility staffperson Craig A. Severance based on historical outcomes in the United States said costs for nuclear power can be expected to run $0.25–0.30 per kWh. A 2008 study concluded that if carbon capture and storage were required then nuclear power would be the cheapest source of electricity even at $4,038/kW in overnight capital cost. In 2009, MIT updated its 2003 study, concluding that inflation and rising construction costs had increased the overnight cost of nuclear power plants to about $4,000/kW, and thus increased the power cost to $0.084/kWh.