Myrle Diefendorf, Since you have an Orchid like this... Have you ever ran into Black marks on the new growth before? and if so is it bad/good.. Or do you even know?
It means that black portion of the leaf is dead for some reason if it goes from the base to the tip of the leaf. It may be a bit of fungus or it may be some black rot from having water set where the leaf comes off the main stem. Try to keep the bulbs above the media and not allow water to stand between the leaf and it's stem. I don't know all that much about them. They like a lot of sun (gradually if you are growing them inside) and putting them out in summer. They do very well here in partial sun. You know in the wild orchids do not grow looking perfect, but we always want ours to look perfect. Sometimes they don't, but they still grow.