Juglans nigra height of and estimated age of 300 years. Juglans nigra Juglans nigra, the eastern black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to eastern North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees. Black walnut is an important tree commercially, as the wood is a deep brown color and easily worked. The fruits, walnuts, are cultivated for
Two-sided market to invest more in R&D or lower their prices, driving out weaker rivals. As a result, mature two-sided network industries are usually dominated by a handful of large platforms, as is the case in the credit card industry. In extreme situations, such as PC operating systems, a single company emerges as the winner, taking almost all of the market. Platform managers must choose the right price to charge each group in a two-sided network and ignoring network effects can lead to mistakes. In "figure 2", pricing without taking network effects into account means finding prices that maximize the areas of