A long, leafless, flowering stem arising directly from a bulb like in onion, is called :

A long, leafless, flowering stem arising directly from a bulb like in onion, is called scape.

Bulbil is also called as bulblet. It is a tiny secondary bulb that forms between a leaf and stem or in place of flowers on certain plants. In some plants, the bud develops into bulbil instead of a flower. It separates from the parent plant and given rise to a new plant. Therefore, it is a vegetative reproduction e.g., Agave, Oxalis. 

A turion is a swollen bud, which contains much-stored food. It is detached from the parent plant and remains inactive through the winter and gives rise to a new plant in the following spring. Turions are found in a number of water plants. Example– Utricularia, Potamogeton, etc.

A liana is a long-stemmed, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight.