have a look at this link
http://www.orchidgeeks.com/forum/gen...home-page.html
you can see the bulbs without leaves are back bulbs.
most back bulbs can be sat on top of Sphagnum moss the bulb may shoot and form a new growth.
back bulbs are called pseudobulbs
pseudobulbs also feed the growth on an orchid as well.
this link also will show you pseudobulbs ( back bulbs ) also
Odm. grande pseudobulb