That is a baby plant (keiki) which the mother plant made because she was dying. You can pot the baby plant when it forms roots. Leave the baby plant and spritz any roots which form until they grow about 1-2 inches. Then cut the spike with the baby plant and set the roots gently in a small pot with some sphagnam moss.

Keep the plant in a bright window until it begins growing into the media. You can then grow the baby outside in summer.

You should figure out what caused the death of the mother plant. Possible causes were poor watering practices (too much, too little). Poor light or tempertures.

Best to search on this site for information about growing this orchid. Your orchid is called a Phalaenopsis.

Jane

Thanks for that. I've had some orchids for years, but I think the pot was the problem on this one - I could never tell whether it was damp or dry. Hopefully the babies will grow on - it was a pretty acid green flower.

Nancy.