An onion, strictly speaking, is a 'bulb' and is a stem.
A root bulb.
An onion is actually a modified stem.
The edible part of the onion is composed mainly of root. There is a small portion of stem in the edible part.
It is a bulb which is root.NOT STEM!
it is a root
a bulb
bulb
the onion is a bulb
Leek is Allium porrum a member of the onion family used for it's underground white stem.
stem
A root. There are turnips and turnip greens the greens is the stem.
Carrot is a root vegetable.
Its a stem.
stem
stem
root
It is a root
affix
a root
Tapioca is a root