x1 [body-part] is the upper/normally exposed part(s) or region(s) of a plant or sedentary organism (stalk/stem/trunk, branches, leaves, flowers, fruit; not root, bulb, or burrowing parts), belonging to plant x2.
Need not be part of plant, but it will usually be for something sedentary with distinctly differentiated anchoring or burrowing body-parts. Potential metaphorical senses: upper/ground (not basement) stories of a building. Application to humans is discouraged, but in that case, it would normally refer to entire body region which is above the hips while standing erect. See also: stani, torso.